Method for making a peroxycarboxylic acid

ABSTRACT

The present invention relates to apparatus and methods for making a peroxycarboxylic acid. The apparatus includes a reaction catalyst and a guard column for pretreating one or more reagents, which can increase the life, activity, and/or safety of the reaction catalyst. The peroxycarboxylic acid compositions made by the method and apparatus can include one or more peroxycarboxylic acids.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/291,600 filed Nov. 8, 2011, which is a divisional of U.S. patentapplication Ser. No. 12/108,202, filed Apr. 23, 2008, now U.S. Pat. No.8,075,857 issued on Dec. 13, 2011, which is a continuation-in-part ofU.S. patent application Ser. No. 11/583,371, filed Oct. 18, 2006, nowU.S. Pat. No. 7,547,421 issued on Jun. 16, 2009, all of which areincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to apparatus and methods for making aperoxycarboxylic acid. The apparatus includes a reaction catalyst and apretreatment column for pretreating one or more reagents, which canincrease the life, activity, and/or safety of the reaction catalyst. Theperoxycarboxylic acid compositions made by the method and apparatus caninclude one or more peroxycarboxylic acids.

BACKGROUND OF THE INVENTION

Present methods for making peroxycarboxylic acids include mixing acarboxylic acid or anhydride with an oxidizing agent, such as hydrogenperoxide, in water and waiting. At ambient conditions, the reaction cantake a week or more to reach desirable concentrations ofperoxycarboxylic acid at equilibrium. In addition, regulations regardingand practices in shipping of ingredients such as hydrogen peroxide andacetic acid can limit the concentration, stability, content, or purityof these reagents and, therefore, of the resulting peroxycarboxylicacid. For example, acetic acid inevitably contains metal due to commonshipping and handling practices. Conventional peroxycarboxylic acidcompositions typically include short chain peroxycarboxylic acids ormixtures of short chain peroxycarboxylic acids and medium chainperoxycarboxylic acids (see, e.g., U.S. Pat. Nos. 5,200,189, 5,314,687,5,409,713, 5,437,868, 5,489,434, 6,674,538, 6,010,729, 6,111,963, and6,514,556).

Ongoing research efforts have strived for improved peroxycarboxylic acidcompositions and methods of making them. In particular, these effortshave strived for methods that can more rapidly make purer and/or morestable peroxycarboxylic compositions even at a point of use.

SUMMARY OF THE INVENTION

The present invention relates to apparatus and methods for making aperoxycarboxylic acid. The apparatus includes a reaction catalyst and apretreatment column for pretreating one or more reagents, which canincrease the life, activity, and/or safety of the reaction catalyst. Theperoxycarboxylic acid compositions made by the method and apparatus caninclude one or more peroxycarboxylic acids.

The present invention includes an apparatus for making peroxycarboxylicacid. In an embodiment, this apparatus can include a first pretreatmentcolumn, a first reaction catalyst column, a first and a second reagentvessel, a plurality of conduits, and a safety system. The first andsecond reagent vessels are in fluid communication with the firstpretreatment column. The first pretreatment column is in fluidcommunication with the first reaction catalyst column. The firstreaction catalyst column can be in fluid communication with a site ofstorage or use of the peroxycarboxylic acid composition. The firstreagent vessel can be configured for containing a liquid hydrogenperoxide composition and the second reagent vessel can be configured forcontaining a liquid carboxylic acid composition. The safety system canbe configured to measure temperature, pressure, metal content, orcombination thereof of the hydrogen peroxide and carboxylic acidcomposition in, at, or before entry to the pretreatment column.

The present method includes a method for making a peroxycarboxylic acid.In an embodiment the method includes pretreating a liquid composition ofa carboxylic acid, hydrogen peroxide, or both with a pretreatmentcolumn. The method can optionally include mixing the pretreated liquidcomposition with a liquid composition of carboxylic acid, hydrogenperoxide or both to yield a composition comprising carboxylic acid andhydrogen peroxide. The method then includes reacting the compositioncomprising carboxylic acid and hydrogen peroxide in the presence of areaction catalyst to produce a peroxycarboxylic acid composition andrecovering the peroxycarboxylic acid composition. The method includesmonitoring temperature, pressure, or metal content of the carboxylicacid, hydrogen peroxide, or both before pretreating, during pretreating,or both. If the temperature, difference in temperatures, pressure,difference in pressures, metal content, or difference in metal contentexceeds a predetermined value, the method includes actuating a pressurerelease valve, stopping flow of one or more reagents, causing water toflow into the apparatus, causing carboxylic acid composition to flowinto the apparatus, shutting down the method, or a combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 schematically represent embodiments of apparatus thatgenerates peroxycarboxylic acid including embodiments of pretreatmentcolumn and reaction catalyst.

FIG. 6 schematically represents embodiments of the safety system andpretreatment column.

FIGS. 7-10 schematically represent embodiments of apparatus thatgenerates peroxycarboxylic acid including embodiments of pretreatmentcolumn, reaction catalyst, and safety system.

FIG. 11 schematically represents an embodiment of apparatus thatgenerates peroxycarboxylic acid in fluid communication with anembodiment of aseptic packaging system.

FIGS. 12 and 13 schematically represent embodiments of apparatus thatgenerates peroxycarboxylic acid including embodiments of pretreatmentcolumn and reaction catalyst.

FIG. 14 schematically represents embodiments of the safety system andreaction catalyst.

FIG. 15 schematically represents embodiments of apparatus that generatesperoxycarboxylic acid including an embodiment of storage system.

FIG. 16 is a flow chart illustrating an embodiment of a process by whichthe controller monitors and/or regulates the concentrations ofperoxycarboxylic acid and/or of hydrogen peroxide in the usecomposition.

FIG. 17 is a flowchart illustrating an embodiment of a “generator check”process by which the controller monitors and regulates operation ofperoxycarboxylic acid generator.

FIG. 18 is a diagram of a beverage plant, including a cold asepticfilling plant, in which either carbonated or non-carbonated beveragescan be prepared and bottled.

Various embodiments of the present invention will be described in detailwith reference to the drawings, wherein like reference numeralsrepresent like parts throughout the several views. Reference to variousembodiments does not limit the scope of the invention, which is limitedonly by the scope of the claims.

DETAILED DESCRIPTION OF THE INVENTION Definitions

As used herein, the phrase “medium chain carboxylic acid” refers to acarboxylic acid that: 1) has reduced or is lacking odor compared to thebad, pungent, or acrid odor associated with an equal concentration ofsmall chain carboxylic acid, and 2) has a critical micellarconcentration greater than 1 mM in aqueous buffers at neutral pH. Mediumchain carboxylic acids exclude carboxylic acids that are infinitelysoluble in or miscible with water at 20° C. Medium chain carboxylicacids include carboxylic acids with boiling points (at 760 mm Hgpressure) of 180 to 300° C. In an embodiment, medium chain carboxylicacids include carboxylic acids with boiling points (at 760 mm Hgpressure) of 200 to 300° C. In an embodiment, medium chain carboxylicacids include those with solubility in water of less than 1 g/L at 25°C. Examples of medium chain carboxylic acids include pentanoic acid,hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoicacid, undecanoic acid, and dodecanoic acid.

As used herein, the phrase “medium chain peroxycarboxylic acid” refersto the peroxycarboxylic acid form of a medium chain carboxylic acid.

As used herein, the phrase “short chain carboxylic acid” refers to acarboxylic acid that: 1) has characteristic bad, pungent, or acrid odor,and 2) is infinitely soluble in or miscible with water at 20° C.Examples of short chain carboxylic acids include formic acid, aceticacid, propionic acid, and butyric acid.

As used herein, the phrase “short chain peroxycarboxylic acid” refers tothe peroxycarboxylic acid form of a short chain carboxylic acid.

As used herein the term “inert metal cations” refers to those metalcations which are substantially unreactive (e.g., do not undergo anundesirable level of reaction) or unreactive with hydrogen peroxide or aperoxycarboxylic acid (i.e., peroxygen species). For example, sodium andpotassium are inert metal cations, whereas iron and copper are not.

As used herein, the term “insoluble” is used to describe a substancethat does not dissolve to give more than a negligible concentration(e.g., <0.1 mg/mL) in a carrier or solvent employed for the carboxylicacid, oxidizing agent, peroxycarboxylic acid, or combination thereof togive a reasonable concentration.

As used herein, a composition or combination “consisting essentially” ofcertain ingredients refers to a composition including those ingredientsand lacking any ingredient that materially affects the basic and novelcharacteristics of the composition or method. The phrase “consistingessentially of” excludes from the claimed compositions and methods asequestrant, builder, chelating agent, or stabilizing agent; unless sucha process or ingredient is specifically listed after the phrase.

As used herein, a composition or combination “substantially free of” oneor more ingredients refers to a composition that includes none of thatingredient or that includes only trace or incidental amounts of thatingredient. Trace or incidental amounts can include the amount of theingredient found in another ingredient as an impurity or stabilizer orthat is generated in a minor side reaction during formation ordegradation of the peroxycarboxylic acid. For example, commerciallyavailable hydrogen peroxide often contains minor amounts of a stabilizersuch as a tin compound or in some cases trace amounts of HEDP.

As used herein, the phrases “objectionable odor”, “offensive odor”, or“malodor” refer to a sharp, pungent, or acrid odor or atmosphericenvironment from which a typical person withdraws if they are able to.Hedonic tone provides a measure of the degree to which an odor ispleasant or unpleasant. An “objectionable odor”, “offensive odor”, or“malodor” has an hedonic tone rating it as unpleasant as or moreunpleasant than a solution of 5 wt-% acetic acid, propionic acid,butyric acid, or mixtures thereof.

As used herein, the term “microorganism” refers to any noncellular orunicellular (including colonial) organism. Microorganisms include allprokaryotes. Microorganisms include bacteria (including cyanobacteria),lichens, fungi, protozoa, virions, viroids, viruses, phages, and somealgae. As used herein, the term “microbe” is synonymous withmicroorganism.

As used herein, the term “object” refers to a material that can beperceived by the senses, directly and/or indirectly. Objects include asurface, including a hard surface (such as glass, ceramics, metal,natural and synthetic rock, wood, and polymeric), an elastomer orplastic, woven and non-woven substrates, a food processing surface, ahealth care surface, and the like. Objects also include a food product(and its surfaces); a body or stream of water or a gas (e.g., an airstream); and surfaces and articles employed in hospitality andindustrial sectors. Objects also include the body or part of the body ofa living creature, e.g., a hand.

As used herein, the phrase “food product” includes any food substancethat might require treatment with an antimicrobial agent or compositionand that is edible with or without further preparation. Food productsinclude meat (e.g. red meat and pork), seafood, poultry, fruits andvegetables, eggs, living eggs, egg products, ready to eat food, wheat,seeds, roots, tubers, leafs, stems, corms, flowers, sprouts, seasonings,or a combination thereof. The term “produce” refers to food productssuch as fruits and vegetables and plants or plant-derived materials thatare typically sold uncooked and, often, unpackaged, and that cansometimes be eaten raw.

As used herein, the phrase “plant product” includes any plant substanceor plant-derived substance that might require treatment with anantimicrobial agent or composition. Plant products include seeds, nuts,nut meats, cut flowers, plants or crops grown or stored in a greenhouse,house plants, and the like. Plant products include many animal feeds.

As used herein, a processed fruit or vegetable refers to a fruit orvegetable that has been cut, chopped, sliced, peeled, ground, milled,irradiated, frozen, cooked (e.g., blanched, pasteurized), orhomogenized. As used herein a fruit or vegetable that has been washed,colored, waxed, hydro-cooled, refrigerated, shelled, or had leaves,stems or husks removed is not processed.

As used herein, the phrase “meat product” refers to all forms of animalflesh, including the carcass, muscle, fat, organs, skin, bones and bodyfluids and like components that form the animal. Animal flesh includesthe flesh of mammals, birds, fishes, reptiles, amphibians, snails,clams, crustaceans, other edible species such as lobster, crab, etc., orother forms of seafood. The forms of animal flesh include, for example,the whole or part of animal flesh, alone or in combination with otheringredients. Typical forms include, for example, processed meats such ascured meats, sectioned and formed products, minced products, finelychopped products, ground meat and products including ground meat, wholeproducts, and the like.

As used herein the term “poultry” refers to all forms of any bird kept,harvested, or domesticated for meat or eggs, and including chicken,turkey, ostrich, game hen, squab, guinea fowl, pheasant, quail, duck,goose, emu, or the like and the eggs of these birds. Poultry includeswhole, sectioned, processed, cooked or raw poultry, and encompasses allforms of poultry flesh, by-products, and side products. The flesh ofpoultry includes muscle, fat, organs, skin, bones and body fluids andlike components that form the animal. Forms of animal flesh include, forexample, the whole or part of animal flesh, alone or in combination withother ingredients. Typical forms include, for example, processed poultrymeat, such as cured poultry meat, sectioned and formed products, mincedproducts, finely chopped products and whole products.

As used herein, the phrase “poultry debris” refers to any debris,residue, material, dirt, offal, poultry part, poultry waste, poultryviscera, poultry organ, fragments or combinations of such materials, andthe like removed from a poultry carcass or portion during processing andthat enters a waste stream.

As used herein, the phrase “food processing surface” refers to a surfaceof a tool, a machine, equipment, a structure, a building, or the likethat is employed as part of a food processing, preparation, or storageactivity. Examples of food processing surfaces include surfaces of foodprocessing or preparation equipment (e.g., slicing, canning, ortransport equipment, including flumes), of food processing wares (e.g.,utensils, dishware, wash ware, and bar glasses), and of floors, walls,or fixtures of structures in which food processing occurs. Foodprocessing surfaces are found and employed in food anti-spoilage aircirculation systems, aseptic packaging sanitizing, food refrigerationand cooler cleaners and sanitizers, ware washing sanitizing, blanchercleaning and sanitizing, food packaging materials, cutting boardadditives, third-sink sanitizing, beverage chillers and warmers, meatchilling or scalding waters, autodish sanitizers, sanitizing gels,cooling towers, food processing antimicrobial garment sprays, andnon-to-low-aqueous food preparation lubricants, oils, and rinseadditives.

As used herein, the phrase “air streams” includes food anti-spoilage aircirculation systems. Air streams also include air streams typicallyencountered in hospital, surgical, infirmity, birthing, mortuary, andclinical diagnosis rooms.

As used herein, the term “waters” includes food process or transportwaters. Food process or transport waters include produce transportwaters (e.g., as found in flumes, pipe transports, cutters, slicers,blanchers, retort systems, washers, and the like), belt sprays for foodtransport lines, boot and hand-wash dip-pans, third-sink rinse waters,and the like. Waters also include domestic and recreational waters suchas pools, spas, recreational flumes and water slides, fountains, and thelike.

As used herein, the phrase “health care surface” refers to a surface ofan instrument, a device, a cart, a cage, furniture, a structure, abuilding, or the like that is employed as part of a health careactivity. Examples of health care surfaces include surfaces of medicalor dental instruments, of medical or dental devices, of electronicapparatus employed for monitoring patient health, and of floors, walls,or fixtures of structures in which health care occurs. Health caresurfaces are found in hospital, surgical, infirmity, birthing, mortuary,and clinical diagnosis rooms. These surfaces can be those typified as“hard surfaces” (such as walls, floors, bed-pans, etc.,), or fabricsurfaces, e.g., knit, woven, and non-woven surfaces (such as surgicalgarments, draperies, bed linens, bandages, etc.,), or patient-careequipment (such as respirators, diagnostic equipment, shunts, bodyscopes, wheel chairs, beds, etc.,), or surgical and diagnosticequipment. Health care surfaces include articles and surfaces employedin animal health care.

As used herein, the term “instrument” refers to the various medical ordental instruments or devices that can benefit from cleaning with astabilized composition according to the present invention.

As used herein, the phrases “medical instrument”, “dental instrument”,“medical device”, “dental device”, “medical equipment”, or “dentalequipment” refer to instruments, devices, tools, appliances, apparatus,and equipment used in medicine or dentistry. Such instruments, devices,and equipment can be cold sterilized, soaked or washed and then heatsterilized, or otherwise benefit from cleaning in a composition of thepresent invention. These various instruments, devices and equipmentinclude, but are not limited to: diagnostic instruments, trays, pans,holders, racks, forceps, scissors, shears, saws (e.g. bone saws andtheir blades), hemostats, knives, chisels, rongeurs, files, nippers,drills, drill bits, rasps, burrs, spreaders, breakers, elevators,clamps, needle holders, carriers, clips, hooks, gouges, curettes,retractors, straightener, punches, extractors, scoops, keratomes,spatulas, expressors, trocars, dilators, cages, glassware, tubing,catheters, cannulas, plugs, stents, scopes (e.g., endoscopes,stethoscopes, and arthoscopes) and related equipment, and the like, orcombinations thereof.

As used herein, “agricultural” or “veterinary” objects or surfacesinclude animal feeds, animal watering stations and enclosures, animalquarters, animal veterinarian clinics (e.g. surgical or treatmentareas), animal surgical areas, and the like.

As used herein, “residential” or “institutional” objects or surfacesinclude those found in structures inhabited by humans. Such objects orsurfaces include bathroom surfaces, drains, drain surfaces, kitchensurfaces, and the like.

As used herein, the phrase “densified fluid” refers to a fluid in acritical, subcritical, near critical, or supercritical state. The fluidis generally a gas at standard conditions of one atmosphere pressure and0° C. As used herein, the phrase “supercritical fluid” refers to a densegas that is maintained above its critical temperature, the temperatureabove which it cannot be liquefied by pressure. Supercritical fluids aretypically less viscous and diffuse more readily than liquids. In anembodiment, a densified fluid is at, above, or slightly below itscritical point. As used herein, the phrase “critical point” is thetransition point at which the liquid and gaseous states of a substancemerge into each other and represents the combination of the criticaltemperature and critical pressure for a substance. The critical pressureis a pressure just sufficient to cause the appearance of two phases atthe critical temperature. Critical temperatures and pressures have beenreported for numerous organic and inorganic compounds and severalelements.

As used herein, the terms “near critical” fluid or “subcritical” fluidrefer to a fluid material that is typically below the criticaltemperature of a supercritical fluid, but remains in a fluid state anddenser than a typical gas due to the effects of pressure on the fluid.In an embodiment, a subcritical or near critical fluid is at atemperature and/or pressure just below its critical point. For example,a subcritical or near critical fluid can be below its criticaltemperature but above its critical pressure, below its critical pressurebut above its critical temperature, or below both its criticaltemperature and pressure. The terms near critical and subcritical do notrefer to materials in their ordinary gaseous or liquid state.

As used herein, weight percent (wt-%), percent by weight, % by weight,and the like are synonyms that refer to the concentration of a substanceas the weight of that substance divided by the weight of the compositionand multiplied by 100. Unless otherwise specified, the quantity of aningredient refers to the quantity of active ingredient.

As used herein, the terms “mixed” or “mixture” when used relating to“peroxycarboxylic acid composition” or “peroxycarboxylic acids” refer toa composition or mixture including more than one peroxycarboxylic acid,such as a composition or mixture including peroxyacetic acid andperoxyoctanoic acid.

As used herein, the term “about” modifying the quantity of an ingredientin the compositions of the invention or employed in the methods of theinvention refers to variation in the numerical quantity that can occur,for example, through typical measuring and liquid handling proceduresused for making concentrates or use solutions in the real world; throughinadvertent error in these procedures; through differences in themanufacture, source, or purity of the ingredients employed to make thecompositions or carry out the methods; and the like. The term about alsoencompasses amounts that differ due to different equilibrium conditionsfor a composition resulting from a particular initial mixture. Whetheror not modified by the term “about”, the claims include equivalents tothe quantities.

For the purpose of this patent application, successful microbialreduction is achieved when the microbial populations are reduced by atleast about 50%, or by significantly more than is achieved by a washwith water. Larger reductions in microbial population provide greaterlevels of protection.

As used herein, the term “sanitizer” refers to an agent that reduces thenumber of bacterial contaminants to safe levels as judged by publichealth requirements. In an embodiment, sanitizers for use in thisinvention will provide at least a 99.999% reduction (5-log orderreduction). These reductions can be evaluated using a procedure set outin Germicidal and Detergent Sanitizing Action of Disinfectants, OfficialMethods of Analysis of the Association of Official Analytical Chemists,paragraph 960.09 and applicable sections, 15th Edition, 1990 (EPAGuideline 91-2). According to this reference a sanitizer should providea 99.999% reduction (5-log order reduction) within 30 seconds at roomtemperature, 25±2° C., against several test organisms.

As used herein, the term “disinfectant” refers to an agent that killsall vegetative cells including most recognized pathogenicmicroorganisms, using the procedure described in A.O.A.C. Use DilutionMethods, Official Methods of Analysis of the Association of OfficialAnalytical Chemists, paragraph 955.14 and applicable sections, 15thEdition, 1990 (EPA Guideline 91-2).

As used in this invention, the term “sporicide” refers to a physical orchemical agent or process having the ability to cause greater than a 90%reduction (1-log order reduction) in the population of spores ofBacillus cereus or Bacillus subtilis within 10 seconds at 60° C. Incertain embodiments, the sporicidal compositions of the inventionprovide greater than a 99% reduction (2-log order reduction), greaterthan a 99.99% reduction (4-log order reduction), or greater than a99.999% reduction (5-log order reduction) in such population within 10seconds at 60° C.

Differentiation of antimicrobial “-cidal” or “-static” activity, thedefinitions which describe the degree of efficacy, and the officiallaboratory protocols for measuring this efficacy are considerations forunderstanding the relevance of antimicrobial agents and compositions.Antimicrobial compositions can effect two kinds of microbial celldamage. The first is a lethal, irreversible action resulting in completemicrobial cell destruction or incapacitation. The second type of celldamage is reversible, such that if the organism is rendered free of theagent, it can again multiply. The former is termed microbiocidal and thelater, microbistatic. A sanitizer and a disinfectant are, by definition,agents which provide antimicrobial or microbiocidal activity. Incontrast, a preservative is generally described as an inhibitor ormicrobistatic composition.

Apparatus for Making Peroxycarboxylic Acid

The present invention relates to an apparatus for making aperoxycarboxylic acid and to methods employing the apparatus. Theapparatus includes a reaction catalyst and a pretreatment column. Thepretreatment column pretreats one or more of the reagents employed inmaking the peroxycarboxylic acid. For example, a cation exchanger inacid form or inert metal (e.g., Na⁺ or K⁺) form can remove positivelycharged contaminants, such as metal ion, from hydrogen peroxide,carboxylic acid, or a mixture of hydrogen peroxide and carboxylic acid.The reaction catalyst catalyzes the reaction of carboxylic acid (orsuitable precursor) with an oxidizing agent (e.g., a peroxide, aperoxide donor, such as a hydrogen peroxide donor) to form aperoxycarboxylic acid. For example, an reaction catalyst that is astrong acid (e.g., a polystyrene sulfonic acid) can catalyze reaction ofhydrogen peroxide with carboxylic acid to form peroxycarboxylic acid.The pretreatment column can increase the life, activity, and/or safetyof the reaction catalyst.

The apparatus can also include a safety system. The safety system canmonitor and/or regulate one or more conditions of the pretreatmentcolumn and/or the reaction catalyst. For example, the safety system canmonitor and/or regulate the pressure, temperature, metal content, and/orpresence of gas resulting from decay of peroxide (e.g., oxygen). Thesafety system can measure one or more of these parameters at or in thepretreatment column, at or in the reaction catalyst, for one or more ofthe reagents before, in, or after a pretreatment column, for thereaction mixture before, in, or after a pretreatment column, for thereaction mixture before, in, or after the reaction catalyst, or morethan one of these (a combination thereof). The safety system can measurea difference in one or more of these parameters between any two pointsin the apparatus, for example, between any two of the listed locations.

In an embodiment, the present apparatus includes one or more reagentvessels, each of which can contain hydrogen peroxide or carboxylicacid(s). These vessels can be in fluid communication with a pretreatmentcolumn, with mixing of the reagents either before or in that column. Thepretreatment column can be in fluid communication with the reactioncatalyst (typically in a column). The resulting peroxycarboxylic acidemerges from the reaction catalyst and can be either used or stored, forexample, in a day tank.

Reaction of the carboxylic acid with the peroxide occurs in the presenceof the reaction catalyst as the reagents are contacted with (e.g., movethrough and/or around) the reaction catalyst at a controlled andpredetermined flow rate. The size of the pretreatment column, the sizeof the bed of reaction catalyst, and the residence time in each of theseare predetermined and controlled to provide the desired amount (often asmuch as possible) conversion of carboxylic acid to peroxycarboxylicacid. The size of the column, bed, or bag of reaction catalyst and theresidence time in it are predetermined and controlled to provide thedesired amount (often as much as possible) conversion of carboxylic acidto peroxycarboxylic acid. System parameters, such as the amount ofreaction catalyst, size of the column, bed, or bag of reaction catalyst,and reagent flow rate, for the apparatus can be selected to providesufficient residence time of the reaction mixture on the reactioncatalyst for conversion into the desired peroxycarboxylic acidcomposition. The reaction catalyst can produce peroxycarboxylic acid atconcentrations as high as, for example, about 35 wt-%, for example,about 5 (e.g., 5.3), about 10, about 15, about 20 (e.g., 19), about 25wt-%, about 30 wt-%, or about 35 wt-%.

The apparatus can also include additional useful or desired systems suchas fittings, valves, pumps, mixing chambers, water or additive supplyconnections, commonly employed for operation of systems including bedsor columns of catalyst or cation exchanger.

The present apparatus can employ reagents that include only volatilecomponents or only insignificant amounts of non-volatile components.Insignificant amounts of non-volatile compounds include an amountacceptable on a food or beverage container (e.g., an aseptic package)after washing and drying. For example, the present apparatus can employreagents that do not include or are substantially free of stabilizer orchelating agent (e.g., HEDP). By way of further example, the presentapparatus can employ reagents that are phosphate-free.

Accordingly, the present apparatus can produce peroxycarboxylic acidcompositions that include only volatile components or only insignificantamounts of non-volatile components. For example, the present apparatuscan produce peroxycarboxylic acid compositions that do not include orare substantially free of stabilizer or chelating agent (e.g., HEDP). Byway of further example, the present apparatus can produceperoxycarboxylic acid compositions that are phosphate-free.

Pretreatment Column

In an embodiment, the apparatus includes one or more pretreatmentcolumns each in fluid communication with a conduit from a single reagentvessel. The pretreatment column can be coupled directly to the bed, bag,or column of reaction catalyst. Alternatively, the pretreatment columncan be in fluid communication with second pretreatment column that isalso in fluid communication with a source of a second reagent. Thepretreatment column can be in fluid communication with a conduit for thesecond reagent (pretreated or not) in which the reagents mix beforeentry into the second pretreatment column. The size of the pretreatmentcolumn and the residence time in the pretreatment column arepredetermined and controlled to provide the desired amount ofcontaminant removal from the pretreated composition.

In an embodiment, the apparatus includes a plurality of (e.g., two)pretreatment columns coupled in parallel between a plurality of reagentvessels and the reaction catalyst. Reagent flow through conduits can becontrolled by valve systems. Flow can be directed through a pretreatmentcolumn until that pretreatment column has received sufficient use or isin a condition that indicates it is no longer fit for use. During use ofthe first pretreatment column, the second pretreatment column can remainready for use. The valve system can then direct flow through the secondpretreatment column when the first is no longer to be used. The columnthat is not being used can be replaced, maintained, washed, or the like.For ease of replacement, the pretreatment column can be a cartridge thatis quickly and easily removed from and placed into the apparatus. Apretreatment column can be washed with, for example, a dilute strongmineral acid, such as sulfuric acid.

Alternatively, the pretreatment column or system can be configured as apretreatment bed or pretreatment bag. The pretreatment bed or bag can beemployed in place of the pretreatment column in the embodimentsdescribed herein.

Use of the apparatus can continue while one of the pretreatment columnsis being maintained or replaced. Changing columns can be done accordingto a predetermined schedule. Alternatively, the condition of thepretreatment column that is in use can be measured by the safety system,which can also control the valve system.

In an embodiment, the pretreatment column is a cartridge or segment thatprecedes the reaction catalyst and that can be within the column, bag,or bed that contains the reaction catalyst. Such a cartridge can beexchanged into and out of the column, bag, or bed of reaction catalyst.In an embodiment, the pretreatment column can be a portion of cationexchanger at the entry to or beginning of the column, bag, or bed ofreaction catalyst. This portion is configured to be removed and replacedwhen, for example, the safety system so indicates or after a certainamount of use.

Reaction Catalyst

The reaction catalyst can be in one or more beds, bags, or columns. Thebeds, bags, or columns can be coupled in series, in parallel, or withsome in series and some in parallel. In an embodiment, the apparatusincludes four columns containing reaction catalyst and connected inseries. In other embodiments, the apparatus includes up to about 10columns of reaction catalyst, for example one to ten columns, forexample, two, three, four, or five columns.

Reagent flow through beds, bags, or columns of reaction catalyst can becontrolled by a valve system. Flow can be directed through a bed, bag,or column until that bed, bag, or column has received sufficient use oris in a condition that indicates it is no longer fit for use. During useof a first bed, bag, or column, a second bed, bag, or column can remainready for use. The valve system can then direct flow through the secondbed, bag, or column when the first is no longer to be used. During useof a first set of beds, bags, or columns, a second set of beds, bags, orcolumns can remain ready for use. The valve system can then direct flowthrough the second set of beds, bags, or columns when the first set isno longer to be used. The bed, bag, or column (or set thereof) that isnot being used can be replaced, maintained, washed, or the like. Use ofthe apparatus can continue while one of the (sets of) beds, bags, orcolumns is being maintained or replaced. The condition of the bed, bag,or column that is in use can be measured by the safety system, which canalso control the valve system.

Safety System

The apparatus can include a safety system that can measure one or moreproperties of the pretreatment column, of the reaction catalyst, orboth. For example, the safety system can measure pressure (e.g.,increased pressure), temperature (e.g., increased temperature), or both.An increase in temperature or pressure from a nominal value for apretreatment column can indicate, for example, unwanted active metal ioncatalyzed decomposition of hydrogen peroxide. For example, the safetysystem can measure a difference in temperature between two points in oraround (e.g., before and after or before and in) the pretreatmentcolumn. An increase in the difference in temperature or difference inpressure from a nominal value for two points in or around a pretreatmentcolumn can indicate, for example, unwanted active metal ion catalyzeddecomposition of hydrogen peroxide. The point or points at whichtemperature or pressure is measured can be selected to provide thedesired sensitivity to contamination or decomposition. The safety systemcan include a manometric sensor for measurements of values or changes invalues.

The safety system can measure pressure, temperature, difference inpressure, difference in temperature, or a combination thereof andprovide a perceptible signal if one or more of these increases above apredetermined level. Pressure, temperature, difference in pressure,difference in temperature, or a combination thereof above a certainlevel can indicate danger from the reaction of peroxide with metals. Thelevel of pressure, temperature, difference in pressure, difference intemperature, or a combination thereof at which safety system provides aperceptible signal can be selected to allow intervention to avoidundesirable or unsafe conditions.

The safety system, upon detecting pressure, temperature, difference inpressure, difference in temperature, or a combination thereof above thepreselected level, can provide a perceptible signal that alerts theoperator to interrupt operation of the apparatus by, for example,actuating a pressure release valve, stopping flow of one or morereagents, causing water to flow into the apparatus, causing carboxylicacid composition to flow into the apparatus, shutting down theapparatus, or a combination thereof. The safety system, upon detectingpressure, temperature, difference in pressure, difference intemperature, or a combination thereof above the preselected level, canprovide a perceptible signal that alerts the operator to switch toanother pretreatment column or bed or column of reaction catalyst.

The safety system can provide a signal to a controller (e.g., acontrollable logic controller) and the controller can actuate a pressurerelease valve, stop flow of one or more reagents, cause water to flowinto the apparatus, cause carboxylic acid composition to flow into theapparatus, shut down the apparatus, or a combination thereof. The safetysystem, upon detecting pressure, temperature, difference in pressure,difference in temperature, or a combination thereof above thepreselected level, can provide a signal to a controller to switch toanother pretreatment column or bed or column of reaction catalyst.

The safety system can measure conditions at an inlet or outlet of apretreatment column, within that column (e.g., near the entrance of thecolumn, in the interior of the column, or near the exit from thecolumn), or in a conduit entering or leaving the pretreatment column.Another embodiment of the safety system can quantify the amount of metalthat enters or has entered the pretreatment column or reaction catalyst.

In an embodiment, the safety system is configured to measure temperatureat the entrance to the pretreatment column and in the first 25% of thepretreatment column. Although not limiting to the present invention, itis believed that measuring this difference can be desirable becausecontamination of the pretreatment column can occur in an exponentialgradient and the reaction between the hydrogen peroxide and thecontamination (e.g., metal ions, such as Fe²⁺ or Cu²⁺) on the column isexothermic.

In an embodiment, the safety system can include a processor and twocondition sensors (e.g., temperature sensor, pressure sensor, metalsensor, or the like). The processor can, for example, performcalculations on input received from the condition sensors and provide asignal that can be received and/or perceived by an operator of theapparatus or one or more actuators. In an embodiment, the actuator cansignal, activate, or operate a valve, pump, switch, or other system foractuating a pressure release valve, stopping flow of one or morereagents, causing water to flow into the apparatus, causing carboxylicacid composition to flow into the apparatus, shutting down theapparatus, or a combination thereof.

The safety system can be configured to measure conditions at an inlet oroutlet of a column, bed, or bag of reaction catalyst, within thatcolumn, bed, or bag (e.g., near the entrance, in the interior, or nearthe exit), or in a conduit entering or leaving the reaction catalyst. Inan embodiment, the safety system is configured to measure temperature atthe entrance to the reaction catalyst and in the first 25% of thereaction catalyst.

Additional Systems

The apparatus can also include systems for storing, handling, diluting,and formulating the composition made by the apparatus. For example, theresulting peroxycarboxylic acid that emerges from the reaction catalystcan be either used or stored, for example, in a day tank. The storagesystem can be a vessel such as a day tank or another vessel suitable forcontaining a peroxycarboxylic acid composition between synthesis anduse. Alternatively, a conduit from the apparatus can lead directly to adilution apparatus or point of use.

The apparatus can include dilution and/or formulation systems fordiluting and/or formulating the composition from the apparatus or theday tank. The apparatus can produce a concentrate, which can be dilutedbefore use. The concentration of peroxycarboxylic acid in the usesolution can be, for example, about 2 to about 5000 ppm or about 750 ppmto about 3600 ppm. Additional suitable use dilutions and compositionsare described hereinbelow. The dilution apparatus can add and/or mixinto the peroxycarboxylic acid a diluent or carrier, such as water, toachieve a diluted composition containing, for example, a desired useconcentration of peroxycarboxylic acid. In an embodiment, the dilutionsystem can include a pump that takes in both carboxylic acid compositionand diluent and puts them out in one or more conduits in a desiredproportion. The dilution system can provide the diluted compositiondirectly to the site of use, to the day tank, or to a dilutedcomposition storage system. In an embodiment in which the dilutionsystem applies the diluted composition directly to the site of use, thissystem can include an applicator nozzle. The applicator nozzle can beconfigured to heat the composition while applying it.

In an embodiment, the apparatus and/or the diluting system can beconfigured to add another ingredient to the peroxycarboxylic acidcomposition. A variety of such ingredients are described hereinbelow.For example, the diluting system can add a diluent that contains anadded ingredient. A formulating system can dispense a desired amount ofan added ingredient into the composition or diluted composition. Such asystem is useful for adding an ingredient that is not compatible withsynthesis or storage of peroxycarboxylic acid, such as a quaternaryammonium chloride.

The storage system can include a storage monitor configured to measurethe content of peroxycarboxylic acid, carboxylic acid, and/or hydrogenperoxide in the composition, for example, in a stored use composition.In an embodiment, the diluted composition storage system includes anreplenishing system. The replenishing system can monitor the content ofthe use composition. If, for example, the concentration ofperoxycarboxylic acid decreases below a predetermined level or theconcentration of carboxylic acid increases above a predetermined level,the replenishing system can add more concentrated peroxycarboxylic acidcomposition to the use composition or empty the vessel of the spent usecomposition. The replenishing system can include, for example, flowmeters and a sensor that detects the concentration of peroxycarboxylicacid.

The apparatus can also include a reagent flow control system. Thereagent flow system can monitor the peroxycarboxylic acid compositionafter the reaction catalyst, for example, at an outlet from the lastreaction catalyst column. This system can determine whether thecomposition includes the desired concentration of peroxycarboxylic acid(e.g., the equilibrium concentration). If the composition includes lessthan the desired concentration, the system can slow the flow rate of thereaction mixture through the reaction catalyst to a flow rate thatresults in the desired concentration. The system can calculate thechange in flow rate employing factors including the temperature of thecomposition and the concentration of peroxycarboxylic acid. The desiredconcentration of peroxycarboxylic acid can be a lower limit and thedesired concentration can be any achievable concentration above thatlower limit.

In an embodiment, the present apparatus can include a middle vesselconfigured to receive one or more reagents after the reagent(s) passesthrough the pretreatment column. The middle vessel can be in fluidcommunication with the pretreatment column and the reaction catalyst.The middle vessel can be configured to receive pretreated reagent(s) andto contain them. The middle vessel can be simultaneously in fluidcommunication with a pretreatment column and reaction catalyst. In anembodiment, the middle vessel can be in fluid communication with apretreatment column and with the reaction catalyst at different times orat overlapping times. In an embodiment, the middle vessel can in be in afirst position for receiving reagent(s) from the pretreatment column andtransported to a second position to provide reagents to the reactioncatalyst.

In an embodiment, the present apparatus can include a purificationsystem that removes non-volatile components from one of more of thereagents, e.g., one or more of carboxylic acid and peroxide. In anembodiment, the purification system is configured as a column, bag, orbed of anion exchanger in fluid communication with the source ofhydrogen peroxide and the pretreatment column.

The present apparatus can be in fluid communication with an asepticpackaging system and configured to provide peroxycarboxylic acidcomposition to the aseptic packaging system. The peroxycarboxylic acidcomposition can be ready to use or can require dilution before use inthe aseptic packaging system. In an embodiment, the present apparatuscan provide ready to use peroxycarboxylic acid composition, for example,to a bottle rinse vessel and/or to a cap rinse vessel tank. In anembodiment, the present apparatus can supply a concentrate, which can bemixed with water or another diluent in or by the aseptic packagingsystem. Such a packaging system can include a water vessel or be coupledto a source of purified water. The aseptic packaging system can includea chamber in which bottles are rinsed and a chamber in which caps arecontacted with the diluted or ready to use peroxycarboxylic acidcomposition. The aseptic packaging system can include a recycling systemthat recovers peroxycarboxylic acid composition that has been applied tobottle and/or cap and returns it to the appropriate vessel for reuse orthat reapplies the composition to additional bottles and/or caps.

Embodiments of the Apparatus

In an embodiment, the present apparatus can include two or three reagentvessels, one containing hydrogen peroxide, one containing short chaincarboxylic acid (e.g., acetic acid), and, optionally, a third vesselcontaining medium chain carboxylic acid (e.g., octanoic acid). The shortchain carboxylic acid (e.g., acetic acid) vessel can be coupled by aconduit to a short chain carboxylic acid (e.g., acetic acid)pretreatment column, with mixing of reagents occurring after thiscolumn. The short chain carboxylic acid (e.g., acetic acid) pretreatmentcolumn can include a cation exchanger in acid form or in inert metal(e.g., Na⁺ or K⁺) form, which can remove positively chargedcontaminants, such as metal ion (e.g. non-inert metal ion, e.g., iron(Fe²⁺ and/or Fe³⁺) or copper (Cu²⁺) ion), from the acetic acid. Theinert metal cation can be selected to be only weakly bound by the cationexchanger. Pretreatment columns dedicated to the hydrogen peroxideand/or medium chain carboxylic acid are optional.

In another embodiment, the present apparatus includes a pretreatmentcolumn in fluid communication with a conduit from a single reagentvessel containing a carboxylic acid. In an aspect, the pretreatmentcolumn of the present apparatus is not in fluid communication withconduits from reagents vessels containing hydrogen peroxide. Thepretreatment column is in fluid communication with a conduit from avessel containing a carboxylic acid, such as, for example, short chaincarboxylic acids (e.g., acetic acid) or medium chain carboxylic acids(e.g., octanoic acid), or mixtures of short and medium chain carboxylicacids. The pretreatment column used to treat the carboxylic acidincludes a cation exchange resin or column in acid form, or in inertmetal (e.g., Na⁺ or K⁺) form, which can remove positively chargedcontaminants, such as metal ion (e.g., non-inert metal ion, e.g., iron(Fe²⁺ or Fe³⁺) or copper (Cu²⁺) ion, from the short chain carboxylicacid. In an aspect, mixing of peroxide and/or medium chain carboxylicacid with the short chain carboxylic acid occurs after pretreatment ofthe carboxylic acid in the pretreatment column. In this embodiment, theperoxide and/or medium chain carboxylic acid may or may not bepretreated in a separate column prior to mixing.

Embodiments for Producing a Peroxycarboxylic Acid

In an embodiment, only the short chain carboxylic acid (e.g., aceticacid) has a dedicated pretreatment column and medium chain carboxylicacid is not employed. In an aspect, mixing of peroxide with the shortchain carboxylic acid occurs after pretreatment of the carboxylic acidin the main pretreatment column. The conduit of the mixture of shortchain carboxylic acid (e.g., acetic acid) and hydrogen peroxide couplesto the main pretreatment column and provides these mixed reagents to thecolumn. This embodiment includes four columns of reaction catalyst.These four columns are in series and are coupled by a conduit to themain pretreatment column. At the other end, the four columns feed shortchain peroxycarboxylic acid (e.g., peroxyacetic acid) into a conduitthat leads to either a storage vessel or to a point of use for thiscomposition. Surprisingly, charged contaminants in the peroxide, such asmetal ions, for example, need not be removed by pretreatment to have asafe and effective system for producing a peroxycarboxylic acid usingthe apparatus described herein.

This embodiment can also include a safety system. The safety system caninclude sensors that monitor temperature, for example, in the conduitafter mixing of hydrogen peroxide and short chain carboxylic acid (e.g.,acetic acid) and/or at the inlet to the main pretreatment column. Thesafety system can also include a sensor that monitors temperature withinthe main pretreatment column, e.g., within the first 25% of thepretreatment column. The safety system can provide a perceptible signalwhen temperature difference between the sensor before the mainpretreatment column and in the sensor in the main pretreatment columnincreases above a predetermined level, for example, about 10° C. In thisembodiment, the safety system, provides a perceptible signal to anoperator and/or provides a perceptible signal to a controller. Uponreceipt of the signal, the operator or controller stops flow of reagentsinto the main guard column and/or flushes the conduits and main guardcolumn with water or short chain carboxylic acid (e.g., acetic acid).

This embodiment of the apparatus can also include additional useful ordesired systems such as fittings, valves, pumps, mixing chambers, andwater or additive supply connections useful or advantageous in thisapparatus. This embodiment can also include one or more of the systemsfor storing, handling, diluting, and formulating the composition made bythe apparatus that are described above.

Embodiments for Producing Mixed Peroxycarboxylic Acids

In an embodiment, the present apparatus can include three reagentvessels, one containing hydrogen peroxide, one containing short chaincarboxylic acid (e.g., acetic acid), and, a third vessel containing amedium chain carboxylic acid, such as octanoic acid. The short chaincarboxylic acid (e.g., acetic acid) vessel can be coupled by a conduitto an short chain carboxylic acid (e.g., acetic acid) pretreatmentcolumn, with mixing of reagents occurring after this column. The shortchain carboxylic acid (e.g., acetic acid) pretreatment column can be andoperate as described for the embodiment above. Pretreatment columnsdedicated to the hydrogen peroxide and/or medium chain carboxylic acid(e.g., octanoic acid) are optional.

In this embodiment, the conduits for short chain carboxylic acid (e.g.,acetic acid) and for hydrogen peroxide join and these reagents mixbefore a first main pretreatment column. The main pretreatment columncan be and operate as described for the embodiment above. The conduit ofthe mixture of short chain carboxylic acid (e.g., acetic acid) andhydrogen peroxide couples to the first main pretreatment column andprovides these mixed reagents to the column. This embodiment includes(e.g., four) columns of reaction catalyst dedicated to producing shortchain peroxycarboxylic acid (e.g., peroxyacetic acid). These columns arein series and are coupled by a conduit to the first main pretreatmentcolumn. At the other end, these columns feed short chainperoxycarboxylic acid (e.g., peroxyacetic acid) into a conduit.

This embodiment also includes conduits for medium chain carboxylic acidand hydrogen peroxide that join and mix these reagents before a secondmain pretreatment column. The second main pretreatment column can be andoperate as described for the embodiment above. The conduit of mixedmedium chain carboxylic acid and hydrogen peroxide couples to the secondmain pretreatment column and provides these mixed reagents to thecolumn. This embodiment includes (e.g., four) columns of reactioncatalyst dedicated to producing medium chain peroxycarboxylic acid.These columns are in series and are coupled by a conduit to the secondmain pretreatment column. At the other end, these columns feed mediumchain peroxycarboxylic acid into a conduit.

The short chain peroxycarboxylic acid (e.g., peroxyacetic acid) conduitand the medium chain peroxycarboxylic acid (e.g., octanoic acid) conduitcan send these peracids into a storage and/or mixing vessel to produce amixed peroxycarboxylic acid composition. Alternatively, these conduitscan join to produce a mixed peroxycarboxylic acid composition.

This embodiment can also include a safety system. The safety system caninclude sensors that monitor temperature before and in each pretreatmentcolumn and that responds to an increased temperature difference foreither pretreatment column. This embodiment of the apparatus can alsoinclude additional useful or desired systems such as fittings, valves,pumps, mixing chambers, and water or additive supply connections usefulor advantageous in this apparatus. This embodiment can also include oneor more of the systems for storing, handling, diluting, and formulatingthe composition made by the apparatus that are described above.

Components of the Apparatus Pretreatment Column

The pretreatment column can include any of a variety of cationexchangers, such as strong cation exchangers. Suitable cation exchangersfor the pretreatment column include polystyrene sulfonic acid resins,such as those sold under the tradenames Dowex M31, Dowex DR-2030, DowexMonosphere M-31, Dowex Monosphere DR-2030, Dowex Marathon 545C, Dowex50W X8-H, Dowex 545C, Dowex G26, Amberlyst 15Wet, Amberlyst 15Dry,Amberlyst 31Wet, Amberlyst 131Wet, Amberlyst CH10, Purolite C-100H,Purolite C-150H, Lewatit MonoPlus S 100 H, Lewatit MonoPlus SP 112 H,and the like. Additional cation exchangers suitable for the pretreatmentcolumn include sulfonated tetrafluoroethylene copolymers such as thosesold under the tradenames Nafion NR50 (beads), Nafion SAC-13 (granules),and Nafion 117 (film), and the like. Other cation exchangers suitablefor the pretreatment column include those sold under the trade namesDowex 545C, Dowex G26, which have high ionic capacity. In an embodiment,the pretreatment column includes an alkali metal (e.g., sodium) form ofthe ion exchanger.

Although not limiting to the present invention, it is believed that, allother things being equal, polystyrene sulfonic acid resins with minimalcrosslinking (via divinylbenzene) show an improved selectivity forexchanging early alkali metal (e.g., sodium and potassium) ions for theproblematic transition or heavy metal (e.g., iron and copper) ions.

A suitable pretreatment column can be dimensioned for sufficient flowand binding capacity to support the volume demanded of the apparatus.For example, a pretreatment column in an apparatus that employs 4columns of reaction catalyst, each having a volume of about 10 L, canemploy a pretreatment column having a volume of about 5 L. For example,a pretreatment column in an apparatus that produces about 11 (e.g.,10.7) liters per hour of peracid composition can employ a pretreatmentcolumn including about 4 (e.g., 3.9) L of resin. For example, apretreatment column in an apparatus that produces about 20 (e.g., 21.3)liters per hour of peracid composition can employ a pretreatment columnincluding about 8 (e.g., 7.8) mL of resin. For example, a pretreatmentcolumn in an apparatus that produces about 45 (e.g., 42.6) liters perhour of peracid composition can employ a pretreatment column includingabout 15 (e.g., about 15.5) L of resin.

A pretreatment column can be configured for advantageous ease ofcleaning the resin or exchanging the column. For example, thepretreatment column can be in fluid communication with the inlet andoutlet conduits with quick connect couplings. Suitable quick connectcouplings include Parkers Indi-Lok (Stratoflex) or Slide-Lok coupling orCole-Parmers, EW-31306-16 couplings, the materials of construction beingpreferably polypropylene, polyethylene or polyfluorocarbon. Quickconnect couplings are also used for the acid backflush, inlets andoutlets which can be operated by the controller or operated manually.The pretreatment column can be a cartridge that can be exchanged in andout of the apparatus. Suitable cartridges can be machined from Schedule40 Polypropylene, or high density polyethylene tubing and are fittedwith manometric and or temperature sensors which can be coupled to thecontroller.

The apparatus can be configured to accept only cartridges suitable foruse in the apparatus. For example, the apparatus and/or cartridge caninclude a fitting, radio frequency identification circuit, or otherelectronic device (e.g., a logic chip or bar code and reader) toindicate to the apparatus that the cartridge is suitable for use in theapparatus. For example, the cartridge can include a programmable devicethat stores the number of times the cartridge has been rinsed. Thecartridge and/or apparatus can indicate after a predetermined number ofwashes that the cartridge is no longer suitable for use. The indicationcan result in the cartridge being locked out of the apparatus.Similarly, the apparatus can be configured to lock out a cartridge thatis not appropriate for use in the apparatus.

For example, a transponder programmed with an identifier can bepositioned on the pretreatment column and/or reaction catalyst. Thiswill allow identification of the pretreatment column and/or reactioncatalyst as suitable for the present apparatus. For example, thetransponder can be placed on or molded into the pretreatment columnand/or reaction catalyst. A small injectable transponder ( 1/16″×½″)would work best on a pretreatment column and/or reaction catalyst, inpart because of its ease of placement. Also, while it would be possibleto mold the transponder into the rack at the time the rack ismanufactured, being able to retrofit existing racks may be desirable. Inalternative embodiments, other sizes of transponders are acceptable.

The transponder can be placed in any suitable location on or in thepretreatment column and/or reaction catalyst. In an embodiment, aparticular orientation of the pretreatment column and/or reactioncatalyst can be enforced by off-setting the transponder on one side orend of the pretreatment column and/or reaction catalyst and off-settingthe transponder antenna appropriately.

The transponder can be pre-programmed with unique identifyinginformation, such as an identifier value indicating the type ofpretreatment column and/or reaction catalyst being used. An example of atransponder that may be used is Destron/IDI Injectable Transponder ModelTX1400L. The Injectable Transponder is a passive radio-frequencyidentification tag, designed to work in conjunction with a compatibleradio-frequency ID reading system.

In an alternative embodiment, image identification could also be used,wherein each pretreatment column and/or reaction catalyst could beidentified before it is received in the present apparatus visually. Anexample of visual identification would be where the machine operatorcould have a choice of several different icons on a computer screenwhich will match the pretreatment column and/or reaction catalyst placedin the apparatus.

Identification of the pretreatment column and/or reaction catalyst couldbe done, for example, by use of specifically designed pretreatmentcolumn and/or reaction catalyst; by use of optical recognition; by useof bar codes; by color of the pretreatment column and/or reactioncatalyst; or by use of a proximity sensor.

An embodiment of the present apparatus includes a transceiver, which isable to detect the type of pretreatment column and/or reaction catalystfrom the identifier, and communicate that identifying information to aprocessor. The transceiver generally includes a transponder antennawhich can located on the outer edge of the apparatus adjacent to thepretreatment column and/or reaction catalyst and its transponder. Thetransponder antenna could also be located within the apparatus. Thetransceiver also includes a transponder interface, which is coupled tothe processor in order for the identifying information to be received bythe processor, and subsequently in order to be looked up in the storagedevice.

For the detector, a barcode scanner similar to the type used in asupermarket could also be utilized in an embodiment. An infrared scanneror proximity sensor could be used. Examples of scanners that may be usedare Destron-Fearing Corporation's (of South St. Paul, Minn.) PocketReader and Pocket Reader EX Scanners. Corresponding bar codes areaffixed to the rack for detection by the bar code scanner.

Reaction Catalyst

The reaction catalyst can include any of a variety of cation exchangers,such as strong cation exchangers. In an embodiment, the reactioncatalyst is the protonated form of the cation exchanger. Suitable cationexchangers as the reaction catalyst include polystyrene sulfonic acidresins, such as those sold under the tradenames Dowex M31, DowexDR-2030, Dowex Monosphere M-31, Dowex Monosphere DR-2030, Dowex Marathon545C, Dowex 50W X8-H, Dowex 545C, Dowex G26, Amberlyst 15Wet, Amberlyst15Dry, Amberlyst 31Wet, Amberlyst 131Wet, Amberlyst CH10, PuroliteC-100H, Purolite C-150H, Lewatit MonoPlus S 100 H, Lewatit MonoPlus SP112 H, and the like. Additional cation exchangers suitable as thereaction catalyst include sulfonated tetrafluoroethylene copolymers suchas those sold under the tradenames Nafion NR50 (beads), Nafion SAC-13(granules), and Nafion 117 (film), and the like. Other cation exchangerssuitable as the reaction catalyst include those sold under the tradenames Dowex 545C, Dowex G26, which have high ionic capacity.

Additional suitable reaction catalysts include an inorganic compoundthat is or includes an insoluble strong acid, in certain embodiments,with a high surface area/weight ratio. Such inorganic catalysts includethose sold under generic names such as “Sulfated Zirconia”, “SilicaStabilized Tetragonal Zirconia” and “Tungstated Zirconia” (fromSaint-Gobain Norpro). Suitable inorganic catalysts also include zirconiaoxides sold as generic “ZrO₂” (MEI Chemicals). A zirconia oxide can betreated with sulfuric acid followed by calcination at ˜700 deg C toproduce a “sulfated Zirconia.” Other suitable inorganic catalystsinclude sulfated silicas or silicon oxides, sulfated or acidifiedzeolites, sulfated or acidified aluminum oxides, and phosphonic acidderivatized silicon oxides (e.g., those sold under the tradename“Si-POH₂” and an alkylphosphonic acid modified silica from PhosphononicsLtd.)

A suitable column, bag, or bed of reaction catalyst can be dimensionedfor sufficient flow and catalyst capacity to support the volumesdemanded of the apparatus. For example, a column, bag, or bed ofreaction catalyst in an apparatus that produces about 40 (e.g., 41)liters per hour of peracid composition can employ four columns ofreaction catalyst each with volume of about 30 (e.g., 31) L and being 1meter in length and 20 cm in diameter. A bed, bag, or column of reactioncatalyst can be dimensioned in any suitable dimension for achieving thedesired flow. Suitable dimensions include about 0.1 (e.g., 0.13) toabout 15 (e.g., 13) meters in, for example, length by about 10 to about100 cm in, for example, diameter. Suitable columns include thosedimensioned about 15 (e.g., 13) meters in length by about 10 cm indiameter. Suitable columns include those dimensioned about 0.5 (e.g.,0.4) meters in length by about 20 cm in diameter. Suitable columnsinclude those dimensioned about 0.15 (e.g., 0.13) meters in length byabout 100 cm in diameter. A column can be in any of a variety ofconfigurations. For example, a column can be a normal cylindrical tubeor a coiled tube. Suitable coiled tubes include a tube about 60 (e.g.,62) meters long by about 5 cm in diameter in a coil about 1 meter indiameter with about 20 turns. The reaction catalyst can be configured toprovide about 30 to about 300 minutes of contact time of the catalystand the reaction mixture.

A column, bag, or bed of reaction catalyst can be configured foradvantageous ease of cleaning, regenerating, or backflushing the bed,bag, or column. Advantageous features of the column, bag, or bed ofreaction catalyst include a plurality of ports and valves betweensegments of catalyst that allow for selective backflushing of isolatedsegments of the overall catalytic bed as well as venting of theaccumulated gases to facilitate pumping and circulating of cleaning orbackflushing agents.

Reagents

Suitable reagents include hydrogen peroxide at about 5 to about 70 wt-%,about 5 to about 50 wt-%, or about 35 to about 50 wt-% in water; e.g.,hydrogen peroxide at about 35 wt-%, about 45 wt-%, about 50 wt-%, orabout 70 wt-% in water. Suitable reagents include acetic acid at about 5to about 100 wt-% (remainder water) or at about 80 to about 98 wt-%; forexample, acetic acid at about 80 wt-%, about 98 wt-%, or about 100 wt-%.Glacial acetic acid is a suitable form of acetic acid. Suitable reagentsinclude octanoic acid at about 1 to about 10 wt-% in glacial aceticacid.

Additional suitable hydrogen peroxide reagents include urea-hydrogenperoxide or any of a variety of other non-ionic hydrogen peroxidecomplexes. Additional suitable oxidizing reagents include caros acid,acidified sodium persulfate, or other peroxy species which equilibrateto form hydrogen peroxide in water.

Additional suitable acetic acid reagents include acetic anhydride,acetyl chloride, polyvinyl acetate, and mono, di and triacetylglycerine. Additional suitable octanoic acid reagents include about 1 toabout 10 wt-% octanoic acid in propylene glycol; about 1 to about 10wt-% octanoic acid in water with a hydrotrope coupling agent, such assodium octane sulfonate, or acidic forms of xylene sulfonate, toluenesulfonate, dioctyl sulfosuccinate, or other alkyl or aryl sulfonates.Other suitable hydrotropes include fatty alcohol ethoxylate phosphateesters, such as Ecolab's PE 362, Emphos PS-236 or Gafac RA-600.Additional suitable carboxylic acid reagents include C₁ and C₂₀ alkanoicacids; polyprotic acids including glycolic, succinic, glutaric, adipic,citric, malic, or lactic acid; alpha and omega dicarboxylic acids suchas succinic, adipic, pimelic, suberic, azelaic, or sebacic acid.Additional suitable peracid precursors include alcohol ethoxylatecarboxylates and amido or imidocarboxylic acids.

The reagent compositions employed in the present apparatus need notinclude, and in embodiments, lack or are substantially free ofstabilizer or chelating agent (e.g., HEDP). The reagent compositionsemployed in the present apparatus can include only volatile compounds.The reagent compositions including only volatile compounds can bephosphate-free.

In certain embodiments, the composition applied to the reaction catalystincludes about 55 (e.g., 56.5) wt-% carboxylic acid and about 30 (e.g.,30.5) wt-% hydrogen peroxide; about 45 (e.g., 43.6) wt-% carboxylic acidand about 20 (e.g., 20.5) wt-% hydrogen peroxide; about 20 wt-%carboxylic acid and about 30 (e.g., 28) wt-% hydrogen peroxide; about 80(e.g., 78) wt-% carboxylic acid and about 10 (e.g., 7.7) wt-% hydrogenperoxide; or about 5 wt-% carboxylic acid and about 5 wt-% hydrogenperoxide.

In certain embodiments, the composition applied to the reaction catalystincludes about 55 (e.g., 56.5) wt-% short chain carboxylic acid andabout 30 (e.g., 30.5) wt-% hydrogen peroxide; about 45 (e.g., 43.6) wt-%short chain carboxylic acid and about 20 (e.g., 20.5) wt-% hydrogenperoxide; about 20 wt-% short chain carboxylic acid and about 30 (e.g.,28) wt-% hydrogen peroxide; about 80 (e.g., 78) wt-% short chaincarboxylic acid and about 10 (e.g., 7.7) wt-% hydrogen peroxide; orabout 5 wt-% short chain carboxylic acid and about 5 wt-% hydrogenperoxide.

In certain embodiments, the composition applied to the reaction catalystincludes about 20 wt-% medium chain carboxylic acid and about 30 wt-%hydrogen peroxide; about 10 wt-% medium chain carboxylic acid and about20 wt-% hydrogen peroxide; about 5 wt-% medium chain carboxylic acid andabout 20 wt-% hydrogen peroxide; or about 3 wt-% medium chain carboxylicacid and about 20 to about 25 (e.g., 22.5) wt-% hydrogen peroxide.

In certain embodiments, the composition applied to the reaction catalystincludes about 50 (e.g., 48) wt-% short chain carboxylic acid, about 20wt-% medium chain carboxylic acid, and about 10 wt-% hydrogen peroxide;about 55 (e.g., 56) wt-% short chain carboxylic acid, about 10 (e.g., 8)wt-% medium chain carboxylic acid, and about 12 wt-% hydrogen peroxide;about 60 wt-% short chain carboxylic acid, about 2 wt-% medium chaincarboxylic acid, and about 15 (e.g., 13) wt-% hydrogen peroxide; orabout 45 (e.g., 44) wt-% short chain carboxylic acid, about 1 wt-%medium chain carboxylic acid, and about 20 (e.g., 21) wt-% hydrogenperoxide.

In certain embodiments, the present composition includesperoxycarboxylic acid and hydrogen peroxide in a ratio of about 0.3:1 toabout 7:1, about 1:1 to about 3:1, or about 2:1 to about 3:1. Certainembodiments include peroxycarboxylic acid and hydrogen peroxide in aratio of about 2:1 to about 3:1, for example, 2.4:1; peroxycarboxylicacid and hydrogen peroxide in a ratio of about 1:1 to about 2:1, forexample 1.4:1; peroxycarboxylic acid and hydrogen peroxide in a ratio ofabout 0.3:1 to about 1:1, for example 0.4:1; or peroxycarboxylic acidand hydrogen peroxide in a ratio of about 7:1, for example 7.1:1.

In certain embodiments, the reagents used in the present apparatus caninclude impurities, such as metal ions, at levels up to 100 ppm, up to10 ppm, up to 1 ppm, or up to 0.1 ppm. Such impurities can include Fe,Cu, Mn, Ni, Ti, Co or any of the transition metal ions.

Illustrated Embodiments

FIG. 1 illustrates an embodiment of the present apparatus in the form ofperoxycarboxylic acid generator 20. In FIG. 1, one or more reagentsupply vessels 21, for example, first reagent supply vessel 22containing hydrogen peroxide and second reagent supply vessel 24containing one or more carboxylic acids are coupled by first and secondlines 26 and 28, respectively, to guard column 30. Hydrogen peroxide andcarboxylic acid are delivered individually from first and second reagentsupply vessels 22 and 24 via first and second lines 26 and 28,respectively, into a mix line 29 leading into guard column 30. In mixline 29 the reagents combine into a reaction mixture, although combiningmay also occur in guard column 30. Guard column 30 contains a cationexchanger (not shown) that removes metal ions from the reaction mixture.The reaction mixture then proceeds to one or more reactor columns 34 viathird line 32.

Reactor column 34 is packed with strong acid catalyst (not shown).Inside reactor column 34, the reaction mixture of hydrogen peroxide andcarboxylic acid react as they move through the strong acid catalyst at apredetermined, controlled flow rate. System parameters, such as columnsize and reagent flow rate, for the peroxycarboxylic acid generator 20are selected and/or controlled to provide sufficient residence time ofthe reaction mixture on the strong acid catalyst for conversion into thedesired peroxycarboxylic acid composition. Generator design and processcontrol are described in more detail herein below. The peroxycarboxylicacid composition is discharged from a reaction column 34 via third line36, for example, into a holding tank 38.

In an embodiment, a peroxycarboxylic acid generator 20 can also includeone or more additional structural components, such as fittings, valves,pumps, mixing chambers, water or additive supply connections, commonlyemployed for operation of systems including packed columns. For example,flow from each reagent supply vessel can be individually controlled byproviding a valve and a pump proximal to each reagent supply vessel.

Additional representative configurations for peroxycarboxylic acidgenerators 20 of the present invention are provided below. Aspects ofthe various configurations shown below may be combined or separated topresent still further configurations of peroxycarboxylic acidgenerators. As in FIG. 1, basic components such as control valves,fittings and pumps which may be present are omitted from the schematicrepresentation for clarity.

In an embodiment, peroxycarboxylic acid generator 20 includes one ormore guard columns 30 in the form of a reagent guard column 40, which ispositioned to receive material from one of first reagent supply vessel22 or second reagent supply vessel 24. The output from reagent guardcolumn 40 can go directly to a reactor column 34. The reagent guardcolumn 40 can be positioned in the fluid flow between the first reagentsupply vessel 22 or second reagent supply vessel 24 and the reactorcolumn 34.

FIG. 2 illustrates an embodiment of the present peroxycarboxylic acidgenerator 20 including two reagent guard columns 40. In the embodimentshown in FIG. 2, a reagent guard column 40 is positioned in first line26 connecting the hydrogen peroxide supply vessel 22 with the guardcolumn 30 and another reagent guard column 40 is placed in second line28 connecting the carboxylic acid supply vessel 24 with the guard column30. Other embodiments can include only one (either one) of these reagentguard columns 40 and/or can omit the guard column 30. Reagent guardcolumn 40 can be configured as a cartridge that can be readily removedand replaced in the peroxycarboxylic acid generator 20. The othercomponents in FIG. 2 are as described above for FIG. 1.

In another embodiment, peroxycarboxylic acid generator 20 includes aplurality of guard columns 30. FIG. 3 schematically illustrates anembodiment including two guard columns 30, the second in the form ofsecond guard column 130. As illustrated, guard column 30 and secondguard column 130 are positioned in parallel between the first and secondreagent supply vessels 22 and 24 and reactor column 34. Reagent flowthrough first and second lines 26 and 28 into one or both of guardcolumn 30 and second guard column 130 under the control of valves 54.With valves 54 directing flow through guard column 30, that columnbecomes full of contaminants, but second guard column 130 remains readyfor use. When guard column 30 is no longer suitable for use, valves 54can be set to direct flow through second guard column 130. The columnthat is not receiving flow can be washed, maintained, or replaced. Inthis fashion, operation of this embodiment of peroxycarboxylic acidgenerator 20 can continue while either first or second guard column 30or 130 is being maintained or replaced. The condition of first and/orsecond guard column 30 or 130 can be determined by the measuring device(below), which can also control the setting of valves 54.

In another embodiment, peroxycarboxylic acid generator 20 includes aplurality of reactor columns 34. A plurality of reactor columns can beconnected either in series, parallel, or both. FIG. 4 illustrates anembodiment including two reactor columns 34 connected in series. Fifthline 42 couples the two reactor columns. In various embodiments, theperoxycarboxylic acid generator 20 can include up to about ten reactorcolumns 34, for example one to ten reactor columns 34, for example, two,three, four, or five reactor columns 34, for example 4 reactor columns34 coupled in series.

In an embodiment, the present apparatus includes a plurality of reactorcolumns 34 connected in parallel. Such an embodiment can include aplurality of reactor columns 34 coupled in series and also a pluralityof reactor columns 34 coupled in parallel. FIG. 5 schematicallyillustrates such a system. In this illustration, the reaction mixtureflows from guard column 30 to a first pair of reactor columns 34 inseries that are coupled by fifth line 42. The guard column 30 is alsocoupled to a second pair of reactor columns 134 in series that arecoupled by line 142. The first pair of reactor columns 34 and secondpair of reactor columns 134 are connected in parallel. The reactionmixture flows from the first pair of reactor columns 34 to holding tank38 through third line 36. The reaction mixture flows from the secondpair of reactor columns to holding tank 38 through sixth line 136.Reactor valves 44 can direct the flow of reaction mixture through eitherfirst pair of reactor columns 34 or the second pair of reactor columns134.

With the reactor valves 44 set to direct flow through first pair ofreactor columns 34, those columns are subject to wear and can beconsumed or fail, but the second pair of reactor columns 134 remainsready for use. When the first pair of reactor columns 34 is no longersuitable for use, reactor valves 44 can be set to direct flow throughthe second pair of reactor columns 134. The pair of columns that is notreceiving flow can be washed, maintained, or replaced. In this fashion,operation of this embodiment of peroxycarboxylic acid generator 20 cancontinue while either first or second pair of reactor columns 34 or 134is being maintained or replaced. The condition of first and/or secondreactor columns 34 or 134 can be determined by the measuring device(below), which can also control the setting of reactor valves 44.

Monitoring Device

In an embodiment, peroxycarboxylic acid generator 20 can includeapparatus for measuring one or more properties of the cation exchanger,reagents on the cation exchanger, the cation exchanger column assemblyas a whole, the catalyst, the reagents on the catalyst, or the catalystcolumn assembly as a whole. For example, such a device can monitorpressure (e.g., increased pressure), temperature (e.g., increasedtemperature), or both. An increase in temperature or pressure from anominal value can indicate unwanted active metal ion catalyzeddecomposition of hydrogen peroxide.

For example, the monitoring device 46 can measure a difference intemperature between two points in or around (e.g., before and after orbefore and in) the guard column 30. An increase in the difference intemperature or difference in pressure from a nominal value for twopoints in or around a guard column 30 can indicate, for example,unwanted active metal ion catalyzed decomposition of hydrogen peroxide.The point or points at which temperature or pressure is measured can beselected to provide the desired sensitivity to contamination ordecomposition.

FIG. 6 illustrates an embodiment of guard column 30 and monitoringdevice 46, which is an embodiment of the safety system. Monitoringdevice 46 includes controller 48 and first and second sensors 50 and 52,respectively, and lead 54. Lead 54 couples first and second sensors 50and 52 to controller 48. In the illustrated embodiment, first sensor 50monitors the condition (e.g., temperature or pressure) of the reactionmixture in mixing line 29 and second sensor 52 monitors the conditionwithin guard column 30. In an embodiment, second sensor can bepositioned into guard column 30 about 10% to about 25% of the distancealong the axis of guard column 30. This same configuration can beemployed with reagent guard column 40.

Monitoring device 46 can measure a difference in conditions (e.g.,temperature or pressure) between first sensor 50 and second sensor 52.First sensor can be positioned before guard column 30 (or reagent guardcolumn 40) in, for example, first line 26, second line 28, or mixingline 29. Second sensor 52 can be positioned at the entrance of, in, orafter guard column 30 (or reagent guard column 40). For example, secondsensor 52 can be positioned at the inlet 60 to guard column 30, within62 guard column 30 but before the cation exchanger, within 64 the cationexchanger of guard column 30 (near the entrance of the column, in theinterior of the column, or near the exit from the column), within guardcolumn 30 between the cation exchanger and the exit 66 from the guardcolumn 30, or at the outlet 68 from the guard column 30. The secondsensor can be in the same positions in reagent guard column 40. Adifference or an increase in the difference in temperature or pressurefrom a nominal value between first sensor 50 and second sensor 52 canindicate, for example, unwanted active metal ion catalyzed decompositionof hydrogen peroxide.

The device illustrated in FIG. 6 is monitored guard column 56. Any ofthe embodiments illustrated in FIGS. 1-5 can employ monitored guardcolumn 56 in place of guard column 30 or reagent guard column 40. Forexample, FIG. 7 schematically illustrates the embodiment of FIG. 2modified to include monitored guard column 56 in place of guard column30. In an embodiment, one or more of the reagent guard columns 40 can bemonitored guard column 56. For a reagent guard column receivingcarboxylic acid, the sensors can measure metal ion.

Upon measuring a difference in temperature or pressure above apreselected level, monitoring device 46 can provide a detectible signalthat alerts the operator to interrupt operation of the apparatus. Forexample, the operator can actuate a pressure release valve 58, stop flowof one or more reagents, cause water to flow into the guard column 30and/or reactor columns 34, cause carboxylic acid to flow into the guardcolumn 30 and/or reactor columns 34, shut down the peroxycarboxylic acidgenerator 20, or a combination thereof. In an embodiment, the monitoringdevice 46 can provide a signal to the controller 48, which can be acontrollable logic controller, and the controller 48 can actuate apressure release valve 58, stop flow of one or more reagents, causewater to flow into the guard column 30 and/or reactor columns 34, causecarboxylic acid to flow into the guard column 30 and/or reactor columns34, shut down the peroxycarboxylic acid generator 20, or a combinationthereof.

Upon measuring a difference in temperature or pressure above apreselected level, monitoring device 46 can provide a detectible signalthat alerts the operator or that signals the controller 48 to switch toanother guard column. For example, FIG. 8 schematically illustrates theembodiment of FIG. 3 modified to include first and second monitoredguard columns 56 and 156 in place of first and second guard columns 30and 130. In an embodiment, the operator can actuate valves 54 to sendthe reagent flow through a second monitored guard column 156. In anembodiment, the monitoring device 46 can provide a signal to acontroller 48 (e.g., a controllable logic controller) and the controller48 can actuate valves 54 to send the reagent flow through secondmonitored guard column 156.

Another embodiment of the measuring device can quantify the amount ofmetal that enters or has entered the column. For example, metalmonitoring device 68 can be positioned at any of the positions describedfor monitoring device 46 and can provide the detectable signal when theamount of metal in the flow through the system exceeds a predeterminedlevel. Alternatively, the metal monitoring device 68 can provide thedetectable signal when a predetermined amount of metal has passed theposition of the device. The detectable signal can be directed to anoperator or controller for the purposes and responses described above.

FIG. 9 schematically illustrates an embodiment of peroxycarboxylic acidgenerator 20 including first and second reagent vessels 22 and 24. Inthis embodiment, first reagent vessel 22 can contain a short chaincarboxylic acid, such acetic acid (e.g., 98% acetic acid). Secondreagent vessel 24 can contain oxidizing agent, such as hydrogen peroxide(e.g., 35-45% hydrogen peroxide). This embodiment includes one reagentguard column 40, optional second reagent guard column 140, monitoredguard column 56, four reactor columns 34 connected in series, and fivepressure release valves 58. The monitored guard column 56 can be of theconfiguration shown in FIG. 6 (e.g., with sensors before the guardcolumn 30 and in the cation exchanger). The reagent guard column 40 caninclude a cation exchanger in acid form or in inert metal (e.g., Na⁺ orK⁺) form.

FIG. 10 schematically illustrates an embodiment of peroxycarboxylic acidgenerator 20 including first peracid generator 70 and second peracidgenerator 72. First peracid generator 70 is configured schematicallyillustrated in FIG. 9 and described above.

Second peracid generator 72 in FIG. 10 has components generallyconfigured according to FIG. 9 and as described above. Second peracidgenerator 72 is, however, configured for producing medium chainperoxycarboxylic acid. In this embodiment, third reagent vessel 23 isconfigured to contain and supply a medium chain carboxylic acid, such asoctanoic acid (e.g., 5 wt-% octanoic acid in propylene glycol). Secondreagent vessel 124 is configured to contain and supply oxidizing agent,such as hydrogen peroxide (e.g., 35-45% hydrogen peroxide). Thisembodiment includes one reagent guard column 240, optional secondreagent guard column 340, second monitored guard column 156, fourreactor columns 134 connected in series, and five pressure releasevalves 158.

The second monitored guard column 156 can be of the configuration shownin FIG. 6 (e.g., with sensors before the guard column 30 and in thecation exchanger). The reagent guard column 240 can include a cationexchanger in acid form or in inert metal (e.g., Na⁺ or K⁺) form.

Hydrogen peroxide and medium chain carboxylic acid are deliveredindividually from second and third reagent supply vessels 124 and 23 viafirst and second lines 126 and 128, respectively, into a mix line 129leading into guard column 30. In mix line 129 the hydrogen peroxide andmedium chain carboxylic acid reagents combine into a medium chainreaction mixture, although combining may also occur in second monitoredguard column 156.

In the embodiment schematically illustrated in FIG. 10, holding tank 38and second holding tank 138 are optional. Holding tank 38 may beemployed to collect short chain peroxycarboxylic acid composition.Second holding tank 138 may be employed to collect medium chainperoxycarboxylic acid composition. The peroxycarboxylic acidcompositions can then be supplied (e.g., pumped) from these tanks in thedesired proportions into mixed peracid holding tank 70. Alternatively,the holding tanks 38 and 138 can be omitted and the peroxycarboxylicacid compositions can be supplied directly from the reactor columns 34and 134 in the desired proportions. In another embodiment, the generatorincludes one holding tank 38 or 138 and the mixed peracid holding tank70. In this embodiment, holding tank 38 or 138 collects one excessperacid composition and then supplies that to the mixed peracid holdingtank in the desired proportion. One peracid generator 70 or 72 thensupplies peracid composition directly to mixed peracid holding tank 70.

Additional Components and Configurations

FIG. 11 schematically illustrates a system including theperoxycarboxylic acid generator 20 and an aseptic packaging line 74. Theperoxycarboxylic acid generator 20 is configured to provideperoxycarboxylic acid composition to the aseptic packaging line 74.Peroxycarboxylic acid generator 20 can be any of the embodimentsillustrated or described herein.

In this embodiment, the peroxycarboxylic acid composition can be readyto use or can require dilution before use in aseptic packaging. Theperoxycarboxylic acid generator 20 can provide ready to useperoxycarboxylic acid composition directly to bottle rinse tank 78and/or cap rinse tank 80. When the peroxycarboxylic acid composition insupplied as a concentrate, aseptic packaging line 74 can includeoptional water source 76 to supply water for diluting theperoxycarboxylic acid composition. Water and peroxycarboxylic acidcomposition can mix in bottle rinse tank 78 and cap rinse tank 80. Watercan be supplied to the rinse tanks through optional first and secondwater conduits 86 and 88. Peroxycarboxylic acid composition can besupplied to the rinse tanks through peracid conduit 90.

The diluted or ready to use composition can be applied to bottles andcaps at bottle rinse station 82 and cap rinse station 84. The mixingtanks are in fluid communication with the rinsing stations throughstation conduits 90. Used composition can be recirculated through firstand second recirculation conduits 92 and 94. The capped bottles can beremoved from the system, for example, by a conveyor (not shown).

FIG. 12 schematically illustrates an embodiment, of the presentperoxycarboxylic acid generator 20 in which guard column 30 is acartridge or segment in reactor column 34. In FIG. 12, one or morereagent supply vessels 21, for example, first reagent supply vessel 22containing hydrogen peroxide and second reagent supply vessel 24containing one or more carboxylic acids are coupled by first and secondlines 26 and 28 and mixing line 29 to guard column 30. Guard column 30contains a cation exchanger (not shown) that removes metal ions from thereaction mixture. The reaction mixture then proceeds to the one or morereactor columns 34. Reactor column 34 is packed with strong acidcatalyst (not shown). The peroxycarboxylic acid composition isdischarged from a reaction column 34 via third line 36, for example,into a holding tank 38. In this embodiment, the guard column 30 and/orcation exchanger can be exchanged into and out of the reaction column34, for example, when the safety system so indicates or after a certainamount of use. The guard column can make up the first about the first 1vol-% to about the first 50 vol-%, for example about 10 to about 15vol-%, of the combined guard and reaction columns 30 and 34. Such aguard column 30 can be employed in any of the illustrated embodiments.

FIG. 13 illustrates an embodiment of the present peroxycarboxylic acidgenerator 20 including middle tank 96. In FIG. 13, one or more reagentsupply vessels 21, for example, first reagent supply vessel 22containing hydrogen peroxide and second reagent supply vessel 24containing one or more carboxylic acids are coupled by first and secondlines 26 and 28 and mixing line 29 to guard column 30. The reactionmixture proceeds through guard column 30 and third line 32 to middletank 96. The reagent or mixed reagents can accumulate in middle tank 96.In an embodiment including a reagent guard column 40 or 140, middle tank96 can be positioned after the reagent guard column 40 or 140 and/orafter guard column 30. Middle tank 96 is coupled to reactor column 34 bymiddle line 98. Reactor column 34 is packed with strong acid catalyst(not shown). The peroxycarboxylic acid composition is discharged from areaction column 34 via third line 36, for example, into a holding tank38.

In an embodiment, middle tank 96 can be configured to receive one ormore reagents from guard column 30 and/or reagent guard column 40 and tocontain the reagent(s). The generator 20 can be configured so thatmiddle tank 96 is simultaneously in fluid communication with guardcolumn 30 and/or reagent guard column 40 and with reactor column 34. Inan embodiment, the generator 20 is configured so that the middle tank 96is in fluid communication with guard column 30 and/or reagent guardcolumn 40 and with reactor column 34 at different times or atoverlapping times. In an embodiment, the generator 20 is configured sothat the middle tank 96 can in be in a first position for receivingreagent(s) from guard column 30 and/or reagent guard column 40 andtransported to a second position to provide reagents to the reactorcolumn 34. That is, in such an embodiment, generator 20 can beconfigured into two separate sets of equipment. The first set ofequipment can include all of the components upstream (in the directionof guard column 30 and/or reagent guard column 40) from middle tank 96and the second set of equipment can include all of the componentsdownstream (in the direction of reactor column 34) from middle tank 96.

Any of the embodiments illustrated in FIGS. 1-13 can include a middletank 96 and/or can be configured as first and second sets of components.

FIG. 14 illustrates an embodiment of reactor column 34 and monitoringdevice 46, which is an embodiment of the safety system. Monitoringdevice 46 includes controller 48 and first and second sensors 50 and 52,respectively, and lead 54. Lead 54 couples first and second sensors 50and 52 to controller 48. In the illustrated embodiment, first sensor 50monitors the condition (e.g., temperature or pressure) of the reactionmixture in third line 32 and second sensor 52 monitors the conditionwithin reactor column 34. In an embodiment, second sensor can bepositioned into reactor column 34 about 10 to about 25% of the distancealong the axis of reactor column 34. Alternatively, the sensors can bepositioned as described above for positioning sensors in guard column30.

In an embodiment such as that illustrated in FIG. 14, the safety systemcan measure conditions at an inlet or outlet of a reactor column 34,within reactor column 34 (e.g., near the entrance of the column, in theinterior of the column, or near the exit from the column), or in aconduit entering or leaving the reactor column 34. Another embodiment ofthe safety system can quantify the amount of metal that enters or hasentered the reactor column 34. In an embodiment, the safety system isconfigured to measure temperature at the entrance to the reactor column34 and in the first 25% of the reactor column 34.

Monitoring and Control of Use Compositions

FIG. 15 is a schematic diagram illustrating an embodiment of aperoxycarboxylic acid generator 20, a controller 48, a POAA holding tank38, a diluent holding tank 16 and a use composition vessel 166.Controller 48 may manage several functions with respect toperoxycarboxylic acid generator 20. For example, controller 48 maycontrol various safety system functions as described above with respectto FIG. 6. Controller 48 may also manage dilution of the concentratecomposition generated by peroxycarboxylic acid generator 20 to form ause composition.

In addition, controller 48 receives concentration data concerning theconcentrations of peroxycarboxylic acid and hydrogen peroxide in the usecomposition via line 180. Based on the concentration data, controller 48may monitor the concentration of peroxycarboxylic acid and/or hydrogenperoxide in the use composition and replenish the use composition whenthese concentrations do not satisfy predetermined criteria. In addition,controller 48 may, based on the concentration data, regulate variousoperating parameters of peroxycarboxylic acid generator 20 to affect theconcentration of peroxycarboxylic acid in the peroxycarboxylic acidconcentrate composition output on line 36.

The concentrations of peroxycarboxylic acid and/or of hydrogen peroxidein the use composition may be determined in any number of ways. Anexample apparatus that may be used to determine the concentrations ofperoxycarboxylic acid and/or of hydrogen peroxide in the use compositionis the Oxycheck System, available from Ecolab Inc. of St. Paul, Minn.The concentration data may also be determined manually. For example,concentration could be obtained by any number of conventional techniquessuch as titration, potentiometric or ampermetic techniques. However, itshall be understood that the invention is not limited in this respect,and that the concentration data may be determined in any number of wayswithout departing from the scope of the present invention.

To manage dilution of the concentrate composition, controller 48 may addand/or mix into the peroxycarboxylic acid concentrate stored in POAAholding tank 38 a diluent, such as water, stored in diluent holding tank164. In one embodiment, controller 48 may regulate one or more valves orpumps that control the flow of the carboxylic acid concentratecomposition from POAA holding tank 38 and diluent from diluent holdingtank 164. Controller 48 may regulate the pump or pumps such that thecarboxylic acid composition and diluent flow into use composition vessel166 in a desired proportion to achieve a use composition containing, forexample, a target concentration of peroxycarboxylic acid.

Controller 48 may replenish the use composition when the concentrationsof peroxycarboxylic acid and/or hydrogen peroxide do not satisfypredetermine criteria. For example, based on the concentration data,controller 48 may regulate addition of peroxycarboxylic acid concentratefrom POAA holding tank 38 or diluent 164 to the use composition 166 toensure that the concentrations of peroxycarboxylic acid and/or hydrogenperoxide in the use composition satisfy the predetermined criteria. If,for example, the concentration of peroxycarboxylic acid in the usecomposition is too low, controller 48 may manage addition of additionalperoxycarboxylic acid concentrate may to the use composition until atarget concentration of peroxycarboxylic acid in the use composition ismet. If the concentration of peroxycarboxylic acid in the usecomposition is too high, controller 48 may manage addition of additionaldiluent to the use composition until the target concentration ofperoxycarboxylic acid in the use composition is met. The targetconcentration may include a specific concentration or may include arange of acceptable concentrations. As another example, if theconcentration of hydrogen peroxide is too high, controller 48 may managethe emptying of the use composition vessel and production of a new usecomposition.

FIG. 16 is a flow chart illustrating the process (200) by whichcontroller 48 monitors and/or regulates the concentrations ofperoxycarboxylic acid and/or of hydrogen peroxide in the usecomposition. Once controller 48 receives the concentration data (202),controller 48 compares the received hydrogen peroxide concentration withpredetermined H₂O₂ target criteria (204). If the received hydrogenperoxide concentration does not satisfy the H₂O₂ target criteria,controller 48 may manage the emptying of the use composition vessel tothe spent use composition (206). In other words, controller 48 maygenerate a control signal or sequence of control signals that cause theuse composition vessel to be emptied of the spent use composition.Controller 48 then manages production of a new use composition bymanaging the flow of peroxycarboxylic acid and diluent into usecomposition vessel 166 (208).

If the hydrogen peroxide concentration satisfies the predetermined H₂O₂target criteria (204), controller 48 compares the peroxycarboxylic acidconcentration in the use composition with predetermined POAA targetcriteria (210). If the peroxycarboxylic acid concentration in the usecomposition does not satisfy the POAA target criteria, controller 48 maymanage replenishing of the use composition. That is, controller 48 mayadjust the peroxycarboxylic acid concentration in the use compositionuntil it satisfies the POAA target criteria (212). To do this,controller 48 may control valves or pumps on POAA concentrate holdingtank 38 and/or diluent holding tank 164 such that a given amount ofperoxycarboxylic acid and/or diluent is added to the use composition inuse composition vessel 166, causing a resultant increase or decrease inthe concentration of peroxycarboxylic acid in the use composition.

In one embodiment, controller 48 may compute the amount ofperoxycarboxylic acid concentrate or diluent to be added to the usecomposition, for example, based on the known concentration ofperoxycarboxylic acid in the use composition and the known or expectedconcentration of peroxycarboxylic acid in the concentrate holding tank38. In another embodiment, controller 48 may iteratively add incrementalamounts of peroxycarboxylic acid and/or diluent to the use compositionuntil the target concentration of peroxycarboxylic acid in the usecomposition is reached.

After a new composition is produced (208) or the POAA concentration inthe use composition is replenished/adjusted (212), controller 48 mayrecord the information concerning the timing, received concentrationdata, amount of use composition made or the relative amounts ofconcentrate or diluent required to bring use composition intosatisfactory compliance with the POAA and/or H₂O₂ target criteria.Controller 48 may also analyze the data and generate various alarms,alerts, or reports based on the stored information and the results ofthe analysis. The alarms, alerts or reports may be communicated to auser via audio alarms such as beepers, buzzers or recorded scriptsand/or visual indicators such as LEDS, numerical, graphical orinteractive displays on peroxycarboxylic acid generator 20. The alarms,alerts or reports may also be sent, either by request or at periodicintervals, to a remote monitoring site via a telephone network, wirelessnetwork, e-mail, local area network, wide area network or the internet.Further, the alarms, alerts or reports may be obtained on site orremotely via a portable device such as a laptop computer, tablet PC,personal digital assistant or other handheld or portable devices.Controller 48 then waits for initiation of the next monitoring period(214), at which point controller 48 will receive the most recentlymeasured concentrations of peroxycarboxylic acid and/or hydrogenperoxide. The next monitoring period may be initiated by a user, eitherlocally or remotely, or controller 48 may be programmed to periodicallymonitor and/or regulate the peroxycarboxylic acid and/or hydrogenperoxide concentrations in the use composition.

The H₂O₂ target criteria and POAA target criteria may vary dependingupon the application to which the use solution is directed. For example,the H₂O₂ target criteria and POAA target criteria may vary dependingupon the degree of efficacy required for the particular application towhich the use solution is directed. In one embodiment, the POAA targetcriteria may be a minimum or a maximum POAA target concentration (e.g.,the measured POAA concentration in the use solution must remain above aminimum POAA concentration or below a maximum POAA concentration). Inanother embodiment, the POAA target criteria may be a range ofacceptable POAA concentrations (e.g., the measured POAA concentration inthe use solution must remain above a minimum POAA concentration andbelow a maximum POAA concentration). Likewise, in one embodiment, theH₂O₂ target criteria may be a minimum or a maximum H₂O₂ targetconcentration (e.g., the measured H₂O₂ concentration in the use solutionmust remain above a minimum H₂O₂ concentration or below a maximum H₂O₂concentration). In another embodiment, the H₂O₂ target criteria may be arange of acceptable H₂O₂ concentrations (e.g., the measured H₂O₂concentration in the use solution must remain above a minimum H₂O₂concentration and below a maximum H₂O₂ concentration).

Another function of controller 48 may be to monitor the overallperformance of peroxycarboxylic acid generator 20. Controller 48 mayanalyze the concentration data concerning the concentrations ofperoxycarboxylic acid and hydrogen peroxide in the use composition toinfer information concerning operation of the peroxycarboxylic acidgenerator 20. For example, peroxycarboxylic acid generator 20 isdesigned to generate a peroxycarboxylic acid concentrate compositionhaving a known, controllable peroxycarboxylic acid concentration. Fromthis known concentration, the concentrate composition in POAA holdingtank 38 is mixed with a known volume of diluent to arrive at acorresponding expected and predictable POAA concentration in the usecomposition stored in use composition vessel 166. Concentration dataindicating a lower than expected POAA concentration in the usecomposition may suggest that the concentration of peroxycarboxylic acidin the POAA concentrate is not at the expected level. This in turn maysuggest that peroxycarboxylic acid generator 20 is not performingaccording to specifications.

Controller 48 may take any of several courses of action whenconcentration data indicating a lower than expected POAA concentrationin the use composition, and thus a lower than expected POAAconcentration in the concentrate composition, is received. For example,controller 48 may compensate for a lower or higher than expected POAAconcentration in the use composition by adjusting certain operatingparameters of peroxycarboxylic acid generator 20 such that the resultingconcentration of peroxycarboxylic acid in the POAA concentratecomposition output on line 36 is increased or decreased. This may be aniterative process which is repeated until a desired concentration ofperoxycarboxylic acid in the POAA concentrate output on line 36 isachieved. For example, controller 48 may control operation of pumps 162Aand/or 162B to adjust the amount of reagent flowing out of reagentsupply vessels 22 and/or 24 and into peroxycarboxylic acid generator 20to cause a corresponding increase or decrease in the concentration ofthe POAA concentrate generated.

Alternatively or in addition to compensating for lower/higher thanexpected concentrations, controller 48 may generate alarms, alerts orreports directed to a user that maintenance of certain components ofperoxycarboxylic acid generator 20 may be required. For example, one orboth of reagent supply vessels 22 or 24 may need to be replenished orpump or valve parameters may require adjustment. Analysis and reports ofthe data may also be generated. For example, statistical trending of theacetic acid and hydrogen peroxide pump rates versus the concentrationsof POAA and hydrogen peroxide within vessel 38 can be used to predictconversion efficiency.

FIG. 17 is a flowchart illustrating an example “generator check” process(220) by which controller 48 monitors and regulates operation ofperoxycarboxylic acid generator 20. Once the concentration dataconcerning the concentrations of peroxycarboxylic acid and/or hydrogenperoxide in the use composition are received (222), controller 48compares the peroxycarboxylic acid concentration to an expected POAAconcentration (224). If the concentration of peroxycarboxylic acid doesnot meet the expected POAA concentration (224), controller 48 may adjustcertain operating parameters of peroxycarboxylic acid generator 20 tocause a resultant change in the peroxycarboxylic acid concentration inthe POAA concentrate (228).

For example, controller 48 may control operation of pumps 162A and/or162B to adjust the amount of reagent flowing out of reagent supplyvessels 22 and/or 24 and into peroxycarboxylic acid generator 20 tocause a corresponding increase or decrease in the concentration of thePOAA concentrate composition output on line 36. Controller 48 may alsoincrease or slow the flow rate of the reaction mixture through thereaction catalyst to a flow rate that results in the desiredconcentration. Controller 48 may calculate the change in flow rateemploying factors including the temperature of the composition and theconcentration of peroxycarboxylic acid. Based on the equilibrationreaction kinetics and thermodynamics, contact time to the reactioncatalyst will determine the end concentration of POAA, just as theconcentration of the reactant species. In this way, the concentration ofperoxycarboxylic acid in the use composition may be maintained within anexpected range, even when generator 20 is not operating entirely up tospecifications.

After the POAA concentration has been checked and adjusted, if necessary(224, 228), controller 48 may record and store the informationconcerning the timing, received concentration data, specific adjustmentsmade to the various operating parameters of generator 20 (i.e., specificadjustments to parameters such as pump and/or valve speed and timing,the amounts of additional POAA or hydrogen peroxide added from reagentvessels 22 and/or 24 to get the system back up to specifications, etc.).This information may be useful to service personnel in performingdiagnostic and maintenance tasks on generator 20, and in monitoringefficiency of peroxycarboxylic acid generator 20. For example, if thesystem continuously generates a product identified as low in POAAcontent, this indicates the system will require service by changing thereaction catalyst.

Controller 48 may also analyze the information and generate variousalarms, alerts, or reports based on this stored information. The alarms,alerts or reports may be communicated to a user via audio alarms such asbeepers, buzzers or recorded scripts and/or visual indicators such asLEDS, numerical, graphical or interactive displays on peroxycarboxylicacid generator 20. The alarms, alerts or reports may also be sent,either by request or at periodic intervals, to a remote monitoring sitevia a telephone network, wireless network, e-mail, local area network,wide area network or the internet. Further, the alarms, alerts orreports may be obtained on site or remotely via a portable device suchas a laptop computer, tablet PC, personal digital assistant or otherhandheld or portable devices.

Controller 48 then waits for initiation of the next generator check(230), at which point controller 48 will receive the most recentconcentration data. The next generator check may be initiated by a user,either locally or remotely, or controller 48 may be programmed toperform generator checks at predetermined periodic intervals. Forexample, controller 48 may repeat the process shown in FIG. 17periodically to ensure that generator 20 is performing in accordancewith specifications and to ensure that the desired level ofperoxycarboxylic acid in the use composition is maintained. Generatorchecks may be performed, for example, on a daily, weekly or monthlybasis.

Methods of Making Peroxycarboxylic Acids

The present invention includes a method for making a peroxycarboxylicacid. The method includes contacting a reagent with a pretreatmentcolumn and a reaction mixture with a reaction catalyst. Contacting caninclude contacting one or more reagents employed in making theperoxycarboxylic acid with, for example, a cation exchanger in acid formor inert metal (e.g., Na⁺ or K⁺) form. The reagent can include hydrogenperoxide, carboxylic acid, or a mixture of hydrogen peroxide andcarboxylic acid. Contacting with the reaction catalyst can includecontacting the catalyst with carboxylic acid (or suitable precursor) andoxidizing agent (e.g., a peroxide) to form a peroxycarboxylic acid. Thereaction catalyst can be a strong acid (e.g., a polystyrene sulfonicacid) to catalyze reaction of hydrogen peroxide with carboxylic acid toform peroxycarboxylic acid. Pretreating one or more reagents canincrease the life, activity, and/or safety of the reaction catalyst.

The method can also include monitoring the safety of the method and theapparatus carrying it out. Monitoring safety can include monitoringand/or regulating one or more conditions of the pretreatment columnand/or the reaction catalyst. Monitoring can include monitoring and/orregulating pressure, temperature, metal content, and/or presence of gasresulting from decay of peroxide (e.g., oxygen). Measuring of one ormore of these parameters can take place at or in the pretreatmentcolumn, at or in the reaction catalyst, for one or more of the reagentsbefore, in, or after a pretreatment column, for the reaction mixturebefore, in, or after a pretreatment column, for the reaction mixturebefore, in, or after the reaction catalyst, or more than one of these (acombination thereof). Measuring can include determining a difference inone or more of these parameters between any two points, for example,between any two of the listed locations.

The method can include providing one or more reagents (e.g., hydrogenperoxide or carboxylic acid(s)) in one or more reagent vessels. Mixingof the reagents can take place before or after one or more of thereagents contact a pretreatment column. Reacting the pretreated reactionmixture or mixture of pretreated reactant with untreated reactant thenoccurs by contacting with the reaction catalyst. Reacting can includecontacting the reaction mixture with the reaction catalyst at acontrolled and predetermined flow rate and/or for a predetermined time.Reacting produces peroxycarboxylic acid. The method can also includeusing or storing the peroxycarboxylic acid.

In an embodiment, the method includes pretreating one or more reagentsindependently of the others. Mixing of the one or more pretreatedreagents with an untreated reagent can then occur before pretreating themixed reagents. Alternatively, each reagent can be pretreatedindependently and then mixed and contacted with the reaction catalyst.Each pretreatment takes place for a predetermined time to provide thedesired amount of contaminant removal from the pretreated composition.

Pretreating can employ a plurality of (e.g., two) pretreatment columnscoupled in parallel. One column can be idle while the other column ispretreating. The method can include switching flow from a usedpretreatment column to a pretreatment column that is ready for use. Themethod can include replacing, maintaining, washing, or the like thepretreatment column that is not being used. Washing can include washingwith, for example, a dilute strong mineral acid, such as sulfuric acid.Washing can include back flushing the pretreatment column. The methodcan continue while one of the pretreatment columns is being maintainedor replaced. Changing columns can be done according to a predeterminedschedule. Alternatively, the method can include monitoring the safety ofthe pretreatment column and replacing it when the monitoring finds apredetermined condition.

Contacting the reaction mixture with the reaction catalyst can occur inone or more beds, bags, or columns, which can be coupled in series, inparallel, or with some in series and some in parallel. The method canemploy contacting with four columns containing reaction catalyst andconnected in series. Reacting can employ a bed, bag, or column untilthat bed, bag, or column has received sufficient use or is in acondition that indicates it is no longer fit for use. During reacting ona first bed, bag, or column, a second bed, bag, or column can remainready for use. The method can include switching flow from the first bed,bag, or column to the second bed, bag, or column when the first is nolonger to be used.

The condition of the bed, bag, or column that is in use can be measuredby the safety system, which can also control the valve system. Changingreaction catalysts can be done according to a predetermined schedule.Alternatively, the method can include monitoring the safety of thereaction catalyst and replacing it when the monitoring finds apredetermined condition. The method can include washing the reactioncatalyst. Washing can include washing with, for example, a dilute strongmineral acid, such as sulfuric acid. Washing can include back flushing abed, bag, or column of the reagent catalyst.

Monitoring safety can include measuring one or more properties of thepretreatment column, of the reaction catalyst, or both. Monitoringsafety can include measuring, for example, pressure (e.g., increasedpressure), temperature (e.g., increased temperature), or both. In anembodiment, measuring can include measuring a difference in temperaturebetween two points in or around (e.g., before and after or before andin) the pretreatment column. Measuring an increase in the difference intemperature or difference in pressure for two points in or around apretreatment column can result in the system providing a perceptiblesignal if the increase is above a predetermined level. Measuring achange above the predetermined level can trigger (manual or automated)actuating a pressure release valve, stopping flow of one or morereagents, causing water to flow into the pretreatment column, causingcarboxylic acid composition to flow into the pretreatment column,shutting down the method, or a combination thereof. Triggering can alsoresult in switching to another pretreatment column or bed or column ofreaction catalyst.

Monitoring safety can include measuring conditions at an inlet or outletof a pretreatment column, within that column (e.g., near the entrance ofthe column, in the interior of the column, or near the exit from thecolumn), or in a conduit entering or leaving the pretreatment column.Monitoring can include measuring temperature at the entrance to thepretreatment column and in the first 25% of the pretreatment column.

The method can also include storing, handling, diluting, and formulatingthe composition made by the method. For example, the method can includeusing or storing the peroxycarboxylic acid. The method can includediluting and/or formulating the composition from the reaction catalystor storage. The method can include diluting a concentrate fore use.Diluting can add and/or mix a diluent or carrier, such as water, intothe peroxycarboxylic acid to achieve a diluted composition containing,for example, a desired use concentration of peroxycarboxylic acid. Thedesired concentration can be, for example, about 2 to about 5000 ppm.Diluting can include adding another ingredient to the peroxycarboxylicacid composition. Formulating can include dispensing a desired amount ofan added ingredient into the composition or diluted composition.

Storing can include monitoring the condition of the composition duringstorage. Monitoring can measure the content of peroxycarboxylic acid,carboxylic acid, and/or hydrogen peroxide in the composition, forexample, in a stored use composition. In an embodiment, the methodincludes replenishing system a stored use composition. Replenishing caninclude monitoring the content of the use composition. If, for example,the concentration of peroxycarboxylic acid decreases below apredetermined level or the concentration of carboxylic acid increasesabove a predetermined level, replenishing then includes adding moreconcentrated peroxycarboxylic acid composition to the use composition oremptying the vessel of the spent use composition.

The method can also include controlling reagent flow. Controllingreagent flow can include monitoring the peroxycarboxylic acidcomposition after the reaction catalyst, for example, at an outlet fromthe last reaction catalyst column. Monitoring can determine whether thecomposition includes the desired concentration of peroxycarboxylic acid(e.g., the equilibrium concentration). If the composition includes lessthan the desired concentration, the controlling can include slowing theflow rate of the reaction mixture through the reaction catalyst to aflow rate that results in the desired concentration. Controlling caninclude calculating the change in flow rate employing factors includingthe temperature of the composition and the concentration ofperoxycarboxylic acid.

The present invention includes a method for making a compositionincluding one peroxycarboxylic acid. The method includes contacting acarboxylic acid with a pretreatment column, mixing the pretreatedcarboxylic acid with hydrogen peroxide, and contacting the reactionmixture with a reaction catalyst to produce the peroxycarboxylic acid.The peroxycarboxylic acid can be a short chain peroxycarboxylic acid(e.g., peroxyacetic acid) or a medium chain peroxycarboxylic acid (e.g.,peroxyoctanoic acid).

The present invention includes a method for making a composition ofmixed peroxycarboxylic acids. The method includes contacting a shortchain carboxylic acid with a first pretreatment column, mixing thepretreated short chain carboxylic acid with hydrogen peroxide, andcontacting the first reaction mixture with a first reaction catalyst toproduce the short chain peroxycarboxylic acid. The method includescontacting a medium chain carboxylic acid with a second pretreatmentcolumn, mixing the pretreated medium chain carboxylic acid with hydrogenperoxide, and contacting the second reaction mixture with a secondreaction catalyst to produce the medium chain peroxycarboxylic acid.Mixing the short chain peroxycarboxylic acid and the medium chainperoxycarboxylic acid produces the mixed peroxycarboxylic acidcomposition.

Methods Conducted at the Site of Use

The present invention also relates to methods of making aperoxycarboxylic acid at the site of its use. For example, the method ofmaking peroxycarboxylic acid described above can be conducted at aplant, e.g. a beverage plant, where the peroxycarboxylic acid will beused. The site of use can be any of a variety of production facilitieswhere a peroxycarboxylic acid might be used. Sites of use include abeverage plant, a food processing plant, a disassembly plant, a meatprocessing plant, or the like. At the site of use, the peroxycarboxylicacid composition can be applied to objects including equipment,containers, and food products. Food products include, for example, plantproduct, product, meat, meat product, poultry, and the like. In anembodiment, the method can include applying the present peroxycarboxylicacid composition to a beverage container, e.g., a plastic bottle or acan.

For example, the method of making peroxycarboxylic acid described abovecan be conducted at a wood pulp producing or paper plant where theperoxycarboxylic acid will be used. By way of further example, themethod of making peroxycarboxylic acid described above can be conductedat a waste treatment plant where the peroxycarboxylic acid will be used.Sites of use include any of a variety of plants that process, use orhandle (e.g., bleach) pulp or make paper, plants that handle waste, suchas industrial waste, food production waste, waste from a beverage plant,waste from a food processing plant, waste from a disassembly plant,waste from a meat processing plant, or the like. At the site of use, theperoxycarboxylic acid composition can be applied to objects includingequipment, pulp, waste, plant surfaces and buildings, other objects inthe plant or facility, or the like. In an embodiment, the method caninclude applying the present peroxycarboxylic acid composition to pulp,to waste, to a waste treatment facility, or to waste treatmentequipment.

The method can include providing carboxylic acid (e.g., acetic acidand/or octanoic acid) and/or oxidizing agent (e.g., hydrogen peroxide)at the site of use (e.g., a beverage plant, a pulp processing plant, ora waste treatment plant) and conducting the present method with thosereagents at the site of use. The method can include shipping thecarboxylic acid (e.g., acetic acid and/or octanoic acid) and/oroxidizing agent (e.g., hydrogen peroxide) to the site of use (e.g., abeverage plant, a pulp processing plant, or a waste treatment plant) forconducting the present method with those reagents at the site of use.The method can include plant or plant organization personnel requestingor ordering the carboxylic acid (e.g., acetic acid and/or octanoic acid)and/or oxidizing agent (e.g., hydrogen peroxide) for delivery to thesite of use (e.g., a beverage plant, a pulp processing plant, or a wastetreatment plant) for conducting the present method with those reagentsat the site of use.

Embodiments of the Method

In an embodiment, the method includes contacting a reaction mixture witha reaction catalyst and monitoring the safety of the method and theapparatus carrying it out. The reaction mixture can include a mixture ofhydrogen peroxide and carboxylic acid. Contacting with the reactioncatalyst can include contacting the catalyst with carboxylic acid (orsuitable precursor) and oxidizing agent (e.g., a peroxide) to form aperoxycarboxylic acid. The reaction catalyst can be a strong acid (e.g.,a polystyrene sulfonic acid) to catalyze reaction of hydrogen peroxidewith carboxylic acid to form peroxycarboxylic acid.

Monitoring safety can include monitoring and/or regulating one or moreconditions of the reaction catalyst. Monitoring can include monitoringand/or regulating pressure, temperature, metal content, and/or presenceof gas resulting from decay of peroxide (e.g., oxygen). Measuring of oneor more of these parameters can take place at or in the reactioncatalyst, for example, for the reaction mixture before, in, or after thereaction catalyst, or more than one of these (a combination thereof).Measuring can include determining a difference in one or more of theseparameters between any two points, for example, between any two of thelisted locations.

Monitoring safety can include measuring one or more properties of thereaction catalyst. Monitoring safety can include measuring, for example,pressure (e.g., increased pressure), temperature (e.g., increasedtemperature), or both. In an embodiment, measuring can include measuringa difference in temperature between two points in or around (e.g.,before and after or before and in) the reaction catalyst. Measuring anincrease in the difference in temperature or difference in pressure fortwo points in or around the reaction catalyst can result in the systemproviding a perceptible signal if the increase is above a predeterminedlevel. Measuring a change above the predetermined level can trigger(manual or automated) actuating a pressure release valve, stopping flowof one or more reagents, causing water to flow into the reactioncatalyst, causing carboxylic acid composition to flow into the reactioncatalyst, shutting down the method, or a combination thereof. Triggeringcan also result in switching to another bed or column of reactioncatalyst.

Monitoring safety can include measuring conditions at an inlet or outletof a column, bed, or bag of reaction catalyst, within the column, bed,or bag of reaction catalyst (e.g., near the entrance, in the interior,or near the exit), or in a conduit entering or leaving the reactioncatalyst. Monitoring can include measuring temperature at the entranceto the reaction catalyst and in the first 25% of the reaction catalyst.

This embodiment need not include pretreating the reagents in withmaterial outside the column, bed, or bag of reaction catalyst.

Peroxycarboxylic Acid Compositions

The present method and apparatus can be employed to make any of avariety of peroxycarboxylic acid compositions. In an embodiment, thepresent method includes a peroxycarboxylic acid composition made by themethod and/or apparatus described hereinabove. A peroxycarboxylic acidcomposition according to the present invention can have advantageousstability, which can be due to a low level of metal ion (e.g., less thanabout 10 ppm or less than about 10 ppb metal ion). The low level ofmetal ion can be achieved and maintained in the present compositionswithout added stabilizer or chelating agent. Accordingly, the presentinvention relates to a stable peroxycarboxylic acid composition lackingor substantially free of stabilizer or chelating agent. The presentinvention also includes a stable peroxycarboxylic acid composition thatincludes only volatile compounds. The present invention also includes aperoxycarboxylic acid composition that includes only volatile compounds.

The term “stable” as applied herein to a peroxycarboxylic acidcomposition means a composition that retains about 90% of theperoxycarboxylic acid for at least about 6 months, that retains about90% of the peroxycarboxylic acid for at least about 7 days, or thatretains about 90% of the peroxycarboxylic acid for at least about 1 day.The stable composition can be one that retains about 95% of theperoxycarboxylic acid for at least about 14 days, that retains about 95%of the peroxycarboxylic acid for at least about 7 days, or that retainsabout 95% of the peroxycarboxylic acid for at least about 3 days. Beingdepleted of trace metals by the generator, the “90%” stability thresholdis generally speaking a function of the equilibrium percarboxylic acidconcentration. The higher concentrations tending to decompose morerapidly.

In certain embodiments, the present peroxycarboxylic acid compositionincludes metal ion at a level less than about 10 ppm, less than about 1ppm, less than about 100 ppb, less than about 10 ppb, or less than about1 ppb ppm. Such metal ion can include Fe, Cu, Mn, Ni, Ti, Co, a mixturethereof, or any of the transition metal ions.

In certain embodiments, the composition at equilibrium includes about 35wt-% peroxycarboxylic acid and about 15 wt-% hydrogen peroxide; about 15(e.g., 17) wt-% peroxycarboxylic acid and about 15 (e.g., 13) wt-%hydrogen peroxide; about 10 (e.g., 9.7) wt-% peroxycarboxylic acid andabout 25 (e.g., 24) wt-% hydrogen peroxide; about 15 (e.g., 13) wt-%peroxycarboxylic acid and about 2 (e.g., 1.9) wt-% hydrogen peroxide, orabout 0.5 wt-% peroxycarboxylic acid and about 5 (e.g., 4.8) wt-%hydrogen peroxide.

In certain embodiments, the composition at equilibrium includes about 35wt-% short chain peroxycarboxylic acid and about 15 wt-% hydrogenperoxide; about 15 (e.g., 17) wt-% short chain peroxycarboxylic acid andabout 15 (e.g., 13) wt-% hydrogen peroxide; about 10 (e.g., 9.7) wt-%short chain peroxycarboxylic acid and about 25 (e.g., 24) wt-% hydrogenperoxide; about 15 (e.g., 13) wt-% short chain peroxycarboxylic acid andabout 2 (e.g., 1.9) wt-% hydrogen peroxide, or about 0.5 wt-% shortchain peroxycarboxylic acid and about 5 (e.g., 4.8) wt-% hydrogenperoxide.

In certain embodiments, the composition at equilibrium includes about 20(e.g., 19) wt-% medium chain peroxycarboxylic acid and about 30 (e.g.,32) wt-% hydrogen peroxide; about 5 (e.g., 6.8) wt-% medium chainperoxycarboxylic acid and about 20 wt-% hydrogen peroxide; about 2(e.g., 2.1) wt-% medium chain peroxycarboxylic acid and about 20 (e.g.,21) wt-% hydrogen peroxide; or about 1 (e.g., 1.2) wt-% medium chainperoxycarboxylic acid and about 20 (e.g., 22) wt-% hydrogen peroxide.

In certain embodiments, the composition at equilibrium includes about 15(e.g., 14) wt-% short chain peroxycarboxylic acid, about 5 (e.g., 5.7)wt-% medium chain peroxycarboxylic acid, and about 3 (e.g., 2.8) wt-%hydrogen peroxide; about 20 (e.g., 19) wt-% short chain peroxycarboxylicacid, about 3 (e.g., 2.7) wt-% medium chain peroxycarboxylic acid, andabout 4 wt-% hydrogen peroxide; about 20 (e.g., 22) wt-% short chainperoxycarboxylic acid, about 1 (e.g., 0.7) wt-% medium chainperoxycarboxylic acid, and about 5 (e.g., 4.6) wt-% hydrogen peroxide;about 15 (e.g., 17.4) wt-% short chain peroxycarboxylic acid, about 0.4wt-% medium chain peroxycarboxylic acid, and about 15 (e.g., 13) wt-%hydrogen peroxide.

In certain embodiments, the present composition includesperoxycarboxylic acid and hydrogen peroxide in a ratio of about 2:1(e.g., 2.4:1); peroxycarboxylic acid and hydrogen peroxide in a ratio ofabout 1.4:1; peroxycarboxylic acid and hydrogen peroxide in a ratio of0.5:1 (e.g., 0.4:1); or peroxycarboxylic acid and hydrogen peroxide in aratio of about 7:1.

The present apparatus and method can be employed to make any of avariety of peroxycarboxylic acid compositions. Compositions that can bemade by the present apparatus and method (which can include addingmaterials such as adjuvant, stabilizing agent, chelating agent, or thelike after forming the peroxycarboxylic acid) include compositionsdisclosed in U.S. Pat. Nos. 5,200,189, 5,314,687, 5,718,910, and6,183,807 and in pending U.S. application Ser. No. 09/614,631, filedJul. 12, 2000, Ser. No. 10/754,426, filed Jan. 9, 2004, and Ser. No.11/030,641, filed Jan. 4, 2005, the disclosures of which areincorporated herein by reference for disclosure of peroxycarboxylic acidcompositions.

Embodiments of the Invention

Embodiments of the invention include, but are not limited to:

In an embodiment, the present invention includes an apparatus for makingperoxycarboxylic acid. This embodiment of the apparatus can include afirst pretreatment column, a first reaction catalyst column, a first anda second reagent vessel, a safety system, a reagent conduit, a reactionmixture conduit, and a peracid conduit. The first and second reagentvessels can be in fluid communication through the reagent conduit withthe first pretreatment column. The first reagent vessel can beconfigured for containing a liquid oxidizing agent composition and thesecond reagent vessel can be configured for containing a liquidcarboxylic acid composition. The reagent conduit can define mixingchamber for the reagents.

The first pretreatment column can be in fluid communication through thereaction mixture conduit with the first reaction catalyst column. Thefirst pretreatment column can be configured for removing metal ion froma mixture of the carboxylic acid composition and the oxidizing agentcomposition. The first reaction catalyst column can be configured forcatalyzing a reaction of the carboxylic acid and the oxidizing agent toproduce peroxycarboxylic acid. The first reaction catalyst column can bein fluid communication through the peracid conduit with a site ofstorage or use of a peroxycarboxylic acid composition. The safety systemincluding a processor, a first condition sensor, and a second conditionsensor. The first condition sensor can be disposed in or on the mixingchamber and can be configured for measuring a condition of the reagents.The second condition sensor can be disposed at or in the firstpretreatment column or in the reaction mixture conduit proximal an exitfrom the first pretreatment column and can be configured for measuringthe condition of the reagents. The processor can be configured fordetermining a difference between the condition measured by the firstcondition sensor and the condition measured by the second conditionsensor and providing a detectable signal if the difference meets orexceeds a predetermined value.

In an embodiment, the first pretreatment column includes a strong cationexchanger in acid form or in inert metal form.

The apparatus can also include a second pretreatment column. The secondpretreatment column can be in fluid communication through the reagentconduit with the second reagent vessel and the first pretreatmentcolumn. The second pretreatment column can be configured for removingmetal ion from the carboxylic acid composition. In an embodiment, thesecond pretreatment column can include a strong cation exchanger in acidform or in inert metal form.

The apparatus can also include a third pretreatment column. The thirdpretreatment column can be in fluid communication through the reagentconduit with the first reagent vessel and the first pretreatment column.The third pretreatment column can be configured for removing metal ionfrom the oxidizing agent composition. In an embodiment, the thirdpretreatment column can include a strong cation exchanger in acid formor in inert metal form.

The apparatus can also include a second, a third, and a fourth reactioncatalyst column. The first, second, third, and fourth reaction catalystcolumns can be coupled in series and can be in fluid communicationthrough the peracid conduit with the site of storage or use of theperoxycarboxylic acid composition.

In an embodiment, the reaction catalyst includes a strong acid catalystthat can be physically removed from the reaction mixture. In anembodiment, the reaction catalyst includes a strong cation exchanger inacid form. In an embodiment, the reaction catalyst includes an inorganiccompound including an insoluble strong acid.

The first and second condition sensors can be configured to measuretemperature, pressure, metal content, or combination thereof. Forexample, the first and second condition sensors are configured tomeasure temperature.

In an embodiment, the safety system is configured to provide adetectable signal if the temperature difference is greater than 10° C.,equal to 10° C., or greater than or equal to 10° C.

The detectable signal can actuates interruption of operation of theapparatus. For example, the detectable signal can actuate interruptionof operation of the apparatus by: actuating a pressure release valve torelease pressure in the first pretreatment column; stopping flow of oneor more reagents into the columns; causing water to flow through thereagent conduit, the first pretreatment column, and the reaction mixtureconduit; causing carboxylic acid composition to flow through the reagentconduit, the first pretreatment column, and the reaction mixtureconduit; shutting down the apparatus; or a combination thereof.

The apparatus can also include a peracid vessel, a dilution system, adilute tank, a replenishing system, and an output conduit. The peracidvessel can be in fluid communication with the peracid conduit and can beconfigured to receive and contain the peroxycarboxylic acid composition.The peracid vessel can be in fluid communication through the outputconduit with the dilution system. The dilution system can be configuredto mix the peroxycarboxylic acid composition and a predetermined amountof carrier to form a diluted composition of a predeterminedconcentration of peroxycarboxylic acid in the dilute tank. Thereplenishing system can be configured to monitor a concentration ofperoxycarboxylic acid, carboxylic acid, oxidizing agent, or combinationthereof in the diluted composition and to add peroxycarboxylic acidcomposition to the diluted composition if the concentration ofperoxycarboxylic acid, carboxylic acid, oxidizing agent, or combinationthereof is less than a predetermined value, equal to a predeterminedvalue, or less than or equal to a predetermined value.

In yet another embodiment, the apparatus can also include a fourthpretreatment column, a fifth reaction catalyst column, a third and afourth reagent vessel, a medium reagent conduit, a medium reactionmixture conduit, and a medium peracid conduit. The third and fourthreagent vessels can be in fluid communication through the medium reagentconduit with the fourth pretreatment column. The third reagent vesselcan be configured for containing a liquid composition of oxidizingagent, the fourth reagent vessel can be configured for containing aliquid composition of medium chain carboxylic acid. The medium reagentconduit can define medium mixing chamber for the medium reagents. Thefourth pretreatment column can be in fluid communication through themedium reaction mixture conduit with the fifth reaction catalyst column.The fourth pretreatment column can be configured for removing metal ionfrom a mixture of the liquid composition of medium chain carboxylic acidand the oxidizing agent composition. The fifth reaction catalyst columncan be configured for catalyzing a reaction of the medium chaincarboxylic acid and the oxidizing agent to produce medium chainperoxycarboxylic acid. The fifth reaction catalyst column can be influid communication through the medium peracid conduit with a site ofstorage or use of a medium chain peroxycarboxylic acid composition. Thefourth pretreatment column can include a strong cation exchanger in acidform or in inert metal form.

In this or another embodiment, the safety system can also include athird condition sensor and a fourth condition sensor. The thirdcondition sensor can be disposed in or on the medium mixing chamber andcan be configured for measuring a condition of the medium reagents. Thefourth condition sensor can be disposed at or in the fourth pretreatmentcolumn or in the medium reaction mixture conduit proximal an exit fromthe fourth pretreatment column and can be configured for measuring thecondition of the medium reagents. The processor can be configured fordetermining a difference between the condition measured by the thirdcondition sensor and the condition measured by the fourth conditionsensor and providing a detectable signal if the difference meets orexceeds a predetermined value.

In this or another embodiment, the second reagent vessel is configuredfor containing a liquid composition of a short chain carboxylic acid.The first pretreatment column is configured for removing metal ion froma mixture of the short chain carboxylic acid composition and theoxidizing agent composition. The first reaction catalyst column isconfigured for catalyzing a reaction of the short chain carboxylic acidand the oxidizing agent to produce short chain peroxycarboxylic acid.

In this embodiment, the third and fourth condition sensors can beconfigured to measure temperature, pressure, metal content, orcombination thereof. For example, the third and fourth condition sensorscan be configured to measure temperature.

This or another embodiment can also include a fifth pretreatment column.The fifth pretreatment column can be in fluid communication through themedium reagent conduit with the fourth reagent vessel and the fourthpretreatment column. The fifth pretreatment column can be configured forremoving metal ion from the liquid composition of medium chaincarboxylic acid. The fifth pretreatment column can include a strongcation exchanger in acid form or in inert metal form.

This or another embodiment can also include a sixth pretreatment column.The sixth pretreatment column can be in fluid communication through themedium reagent conduit with the third reagent vessel and the fourthpretreatment column. The sixth pretreatment column can be configured forremoving metal ion from the liquid composition of oxidizing agent. Thesixth pretreatment column can include a strong cation exchanger in acidform or in inert metal form.

In this or another embodiment, the reaction catalyst can include astrong acid catalyst that can be physically removed from the reactionmixture; a strong cation exchanger in acid form; or an inorganiccompound including an insoluble strong acid.

This embodiment of the apparatus can also include a sixth, a seventh,and an eighth reaction catalyst column. The fifth, sixth, seventh, andeighth reaction catalyst columns can be coupled in series and can be influid communication through the medium peracid conduit with the site ofstorage or use of the medium chain peroxycarboxylic acid composition.

In this embodiment, the peracid vessel can be in fluid communicationwith the medium peracid conduit and can be configured to receive andcontain the medium chain peroxycarboxylic acid composition.

This or another embodiment can also include a second processor. Thesecond processor can be configured for determining a difference betweenthe condition measured by the third condition sensor and the conditionmeasured by the fourth condition sensor and providing a detectablesignal if the difference meets or exceeds a predetermined value.

In an embodiment, the first reaction catalyst column has a volume ofabout 9.6 L. In certain embodiments, each reaction catalyst column has avolume of about 9.6 L. In an embodiment, the fifth reaction catalystcolumn has a volume of about 9.6 L.

In an embodiment, the first pretreatment column has a volume of about4.6 L. In an embodiment, the second pretreatment column has a volume ofabout 4.6 L. In an embodiment, the third pretreatment column has avolume of about 4.6 L. In an embodiment, the fourth pretreatment columnhas a volume of about 4.6 L. In an embodiment, the fifth pretreatmentcolumn has a volume of about 4.6 L. In an embodiment, the sixthpretreatment column has a volume of about 4.6 L.

In an embodiment, the first reagent vessel contains about 35 to about 45wt-% hydrogen peroxide. In an embodiment, the second reagent vesselcontains about 80 to about 98 wt-% acetic acid. In an embodiment, thethird reagent vessel contains about 35 to about 45 wt-% hydrogenperoxide. In an embodiment, the second reagent vessel contains about 1to about 10 wt-% octanoic acid.

The present apparatus can also include a third reagent vessel configuredto contain a liquid medium chain carboxylic acid composition and influid communication through the reagent conduit with the firstpretreatment column. Such an embodiment can also include a fourthpretreatment column. The fourth pretreatment column can be in fluidcommunication through the reagent conduit with the third reagent vesseland the first pretreatment column. The third reagent vessel can containsabout 1 to about 10 wt-% octanoic acid.

The present invention also includes a method for making aperoxycarboxylic acid. This method can include: providing a liquidcomposition of a carboxylic acid and an oxidizing agent; pretreating theliquid composition with a pretreatment column to remove metal ion fromthe mixed composition; measuring a condition of the liquid compositioni) before pretreating and ii) at site of pretreating during pretreating;determining a difference between i) and ii); providing a detectablesignal if the difference meets or exceeds a predetermined value;reacting the pretreated composition in the presence of a reactioncatalyst that can be physically removed from reaction mixture to producea peroxycarboxylic acid composition; and recovering the peroxycarboxylicacid composition.

In an embodiment, pretreating includes contacting the mixed compositionand a strong cation exchanger in acid form or in inert metal form.

This method can also include: pretreating a liquid composition ofcarboxylic acid to remove metal ion from the liquid composition ofcarboxylic acid; and mixing the pretreated liquid composition ofcarboxylic acid and oxidizing agent to form the liquid composition of acarboxylic acid and an oxidizing agent. In this embodiment, pretreatingcan include contacting the liquid composition of carboxylic acid and astrong cation exchanger in acid form or in inert metal form.

This method can also include: pretreating a liquid composition ofoxidizing agent to remove metal ion from the liquid composition ofoxidizing agent; and mixing the pretreated liquid composition ofoxidizing agent and carboxylic acid to form the liquid composition of acarboxylic acid and an oxidizing agent. In this embodiment, pretreatingcan include contacting the liquid composition of oxidizing agent and astrong cation exchanger in acid form or in inert metal form.

The method can include reacting in a column of insoluble reactioncatalyst. This embodiment can also include reacting in a second, athird, and a fourth column of insoluble reaction catalyst. The first,second, third, and fourth reaction catalyst columns can be coupled inseries.

In the method, reacting can include contacting the pretreatedcomposition and an insoluble strong acid catalyst. In an embodiment,reacting can include contacting the pretreated composition and a strongcation exchanger in acid form. In an embodiment, reacting can includecontacting the pretreated composition and an inorganic compoundincluding an insoluble strong acid.

The method can include measuring temperature, pressure, metal content,or combination thereof of the mixed composition. In an embodiment, themethod includes measuring temperature of the mixed composition.

The method can include providing a detectable signal if the temperaturedifference is greater than 10° C., equal to 10° C., or greater than orequal to 10° C.

The method can also include, if the difference meets or exceeds apredetermined value, interrupting of operation of the apparatus by:actuating a pressure release valve to release pressure in an apparatuscarrying out the method; stopping flow of one or more reagents into theapparatus; causing water to flow into the site of pretreating; causingcarboxylic acid composition into the site of pretreating; shutting downthe apparatus; or a combination thereof.

The method can also include mixing the peroxycarboxylic acid compositionand a predetermined amount of carrier to form a diluted composition of apredetermined concentration of peroxycarboxylic acid; storing thediluted composition; monitoring concentration of peroxycarboxylic acid,carboxylic acid, oxidizing agent, or combination thereof in the dilutedcomposition. If the concentration of peroxycarboxylic acid, carboxylicacid, oxidizing agent, or combination thereof is less than apredetermined value, equal to a predetermined value, or less than orequal to a predetermined value, the method can include addingperoxycarboxylic acid composition to the diluted composition.

The method can also include mixing liquid composition of carboxylic acidand oxidizing agent to form the liquid composition of a carboxylic acidand an oxidizing agent. This can form a liquid composition of carboxylicacid that includes about 80 to about 98 wt-% acetic acid. In anembodiment, the oxidizing agent includes about 35 to about 45 wt-%hydrogen peroxide. In an embodiment, the liquid composition ofcarboxylic acid includes about 1 to about 20 wt-% octanoic acid.

The method can include providing a liquid composition of a plurality ofcarboxylic acids and an oxidizing agent. In an embodiment, the methodcan also include mixing a first liquid composition of carboxylic acid, asecond liquid composition of carboxylic acid, and oxidizing agent toform the liquid composition of a plurality of carboxylic acids and anoxidizing agent. In an embodiment, the first liquid composition ofcarboxylic acid includes about 80 to about 98 wt-% acetic acid. In anembodiment, the oxidizing agent includes about 35 to about 45 wt-%hydrogen peroxide. In an embodiment, the second liquid composition ofcarboxylic acid includes about 1 to about 20 wt-% octanoic acid.

This or another embodiment of the method can also include pretreating afirst liquid composition of carboxylic acid to remove metal ion from thefirst liquid composition of carboxylic acid; and including thepretreated first liquid composition of carboxylic acid in the liquidcomposition of a plurality of carboxylic acids and an oxidizing agent.

This or another embodiment of the method can also include pretreating aliquid composition of oxidizing agent to remove metal ion from theliquid composition of oxidizing agent; and including the pretreatedliquid composition of oxidizing agent in the liquid composition of aplurality of carboxylic acids and an oxidizing agent.

This or another embodiment of the method can also include pretreating asecond liquid composition of carboxylic acid to remove metal ion fromthe second liquid composition of carboxylic acid; and including thepretreated second liquid composition of carboxylic acid in the liquidcomposition of a plurality of carboxylic acids and an oxidizing agent.

In an embodiment, the liquid composition of a carboxylic acid and anoxidizing agent includes about 40 to about 50 wt-% acetic acid and about15 to about 25 wt-% hydrogen peroxide. In an embodiment, the liquidcomposition of a carboxylic acid and an oxidizing agent includes about25 to about 35 wt-% acetic acid, about 10 to about 20 wt-% hydrogenperoxide, and about 2 to about 4 wt-% octanoic acid.

The method can include carrying out providing, pretreating, measuring,determining, providing, reacting, and recovering at a site at which theperoxycarboxylic acid composition will be used to reduce the populationof a microbe on an object. This embodiment of the method can alsoinclude delivering carboxylic acid and oxidizing agent to the site. Inan embodiment, the method includes delivering a plurality of carboxylicacids to the site. In an embodiment, the method also includes requestingdelivery of the carboxylic acid and the oxidizing agent from the site.

In an embodiment, the method also includes applying the peroxycarboxylicacid composition to a beverage container at a beverage plant.

The invention also includes a method for making a peroxycarboxylic acid,including. This method includes delivering carboxylic acid and oxidizingagent to a site at which a peroxycarboxylic acid composition will bemade and used; providing a liquid composition of the carboxylic acid andoxidizing agent; pretreating the liquid composition with a pretreatmentcolumn to remove metal ion from the mixed composition; reacting thepretreated composition in the presence of a reaction catalyst that canbe physically removed from reaction mixture to produce theperoxycarboxylic acid composition; recovering the peroxycarboxylic acidcomposition; and applying the peroxycarboxylic acid composition to anobject to reduce the population of microbe on the object.

In an embodiment, the method includes delivering a plurality ofcarboxylic acids to the site. In an embodiment, the method also includesrequesting delivery of the carboxylic acid and the oxidizing agent fromthe site.

In an embodiment, the method also includes applying the peroxycarboxylicacid composition to a beverage container at a beverage plant.

The present invention also includes a method for making a mixedperoxycarboxylic acid composition. The method includes providing aliquid composition of a short chain carboxylic acid and an oxidizingagent; pretreating the mixed short chain composition with a pretreatmentcolumn to remove metal ion from the short chain mixed composition;reacting the pretreated short chain composition in the presence of aninsoluble reaction catalyst to produce a short chain peroxycarboxylicacid composition; providing a liquid composition of a medium chaincarboxylic acid and an oxidizing agent; pretreating the mixed mediumchain composition with a pretreatment column to remove metal ion fromthe mixed medium chain composition; reacting the pretreated medium chaincomposition in the presence of an insoluble reaction catalyst to producea medium peroxycarboxylic acid composition; mixing the short chainperoxycarboxylic acid composition and the medium chain peroxycarboxylicacid composition to produce a mixed peroxycarboxylic acid composition;measuring a condition of the short chain composition i) beforepretreating and ii) at site of pretreating during pretreating;determining a difference between i) and ii); and providing a detectablesignal if the difference between i) and ii) meets or exceeds apredetermined value; measuring a condition of the mixed medium chaincomposition iii) before pretreating and iv) at site of pretreatingduring pretreating; determining a difference between iii) and iv); andproviding a detectable signal if the difference between iii) and iv), orboth differences meets or exceeds a predetermined value.

The present invention also includes a peroxycarboxylic acid compositionmade by a method according to the invention. The method can includeproviding a liquid composition of a carboxylic acid and an oxidizingagent; pretreating the liquid composition with a pretreatment column toremove metal ion from the mixed composition; measuring a condition ofthe liquid composition i) before pretreating and ii) at site ofpretreating during pretreating; determining a difference between i) andii); providing a detectable signal if the difference meets or exceeds apredetermined value; reacting the pretreated composition in the presenceof an reaction catalyst that can be physically removed from reactionmixture to produce a peroxycarboxylic acid composition; and recoveringthe peroxycarboxylic acid composition.

The invention includes a peroxycarboxylic acid composition. Thecomposition can include about 1 to about 35 wt-% peroxycarboxylic acid;about 5 to about 30 wt-% hydrogen peroxide; and less than about 10 ppbmetal. In an embodiment, the composition retains 85% of theperoxycarboxylic acid for at least about 13 days at 140° F. In anembodiment, the composition retains 95% of the peroxycarboxylic acid forat least about 7 days at 140° F. In an embodiment, the compositionincludes about 0.5 to about 35 wt-% short chain peroxycarboxylic acid.In an embodiment, the composition includes about 0.5 to about 20 wt-%medium chain peroxycarboxylic acid. In an embodiment, the compositionincludes about 0.5 to about 35 wt-% short chain peroxycarboxylic acid;and about 0.5 to about 20 wt-% medium chain peroxycarboxylic acid. In anembodiment, the composition includes peroxycarboxylic acid and hydrogenperoxide in a ratio of about 0.5:1 to about 7:1. In an embodiment, thecomposition includes only volatile compounds.

The present invention also includes a system. The system can include aperoxycarboxylic acid generator that outputs a peroxycarboxylic acidconcentrate; a use composition vessel that stores a use compositionincluded of diluted peroxycarboxylic acid concentrate; and a controllerthat receives concentration data concerning the concentrations ofperoxycarboxylic acid and hydrogen peroxide in the use composition andmanages replenishing of the use composition when these concentrations donot satisfy predetermined criteria.

In an embodiment, the controller compares the concentration ofperoxycarboxylic acid to predetermined POAA target criteria and managesaddition of peroxycarboxylic acid concentrate to the use compositionwhen the concentration data indicates that the peroxycarboxylic acidconcentration in the use composition is too low.

In an embodiment, the controller compares the concentration ofperoxycarboxylic acid to predetermined POAA target criteria and managesaddition of diluent to the use composition when the concentration dataindicates that the peroxycarboxylic acid concentration in the usecomposition is too high.

In an embodiment, the controller compares the concentration of hydrogenperoxide to predetermined H₂O₂ target criteria and manages emptying ofthe use composition vessel and production of a new use composition whenthe concentration data indicates that the hydrogen peroxideconcentration in the use composition is too high.

In an embodiment, the controller compares the concentration ofperoxycarboxylic acid to an expected POAA target concentration andregulates operating parameters of the peroxycarboxylic acid generator toaffect the concentration of peroxycarboxylic acid in theperoxycarboxylic acid concentrate output by the peroxycarboxylic acidgenerator.

The present invention also includes a method. The method can includereceiving concentration data concerning the concentrations ofperoxycarboxylic acid and hydrogen peroxide in a use composition;comparing the concentration of peroxycarboxylic acid with predeterminedPOAA target criteria; and automatically replenishing the use compositionwhen the peroxycarboxylic acid concentration does not satisfy thepredetermined POAA target criteria.

In an embodiment of this method, automatically replenishing the usecomposition also includes automatically adding peroxycarboxylic acidconcentrate to the use composition when the concentration data indicatesthat the peroxycarboxylic acid concentration in the use composition istoo low.

In an embodiment of this method, automatically replenishing the usecomposition also includes automatically adding diluent to the usecomposition when the concentration data indicates that theperoxycarboxylic acid concentration in the use composition is too high.

In an embodiment of this method, automatically replenishing the usecomposition also includes automatically emptying the use compositionvessel and producing a new use composition when the concentration dataindicates that the hydrogen peroxide concentration in the usecomposition is too high.

In an embodiment, the method also includes comparing the concentrationof peroxycarboxylic acid to an expected POAA target concentration andregulating operating parameters of the peroxycarboxylic acid generatorto affect the peroxycarboxylic acid concentration in theperoxycarboxylic acid concentrate output by a peroxycarboxylic acidgenerator.

In an embodiment, the methods of the invention include a process forobtaining a high concentration of peroxycarboxylic acid or acids fromthe apparatus of the invention by utilizing feed streams of carboxylicacid or mixtures thereof with minimal water content as well as peroxideor peroxide donor solutions with minimal water content. In an aspect,the minimal water content not only favors equilibration conversion tothe respective peroxycarboxylic acids, but also produces favorablekinetics or rates of generation. In an aspect, the method includes amethod for the preparation of a composition with a high concentration ofperoxycarboxylic acid (e.g., peroxyacetic acid) at the site of its use.In an aspect, a highly concentrated solution of peroxycarboxylic acidmade at the site of use reduces problems associated with shipping andstorage of concentrated solutions of peroxy acids. The site of use canbe any of a variety of production facilities where a peroxycarboxylicacid may be used. Sites of use include, without limitation, a beverageplant, a food processing plant, a disassembly plant, a meat processingplant and the like. At the site of use, the peroxycarboxylic acid can beapplied to objects including equipment, containers, food packagingsurfaces, food products and the like.

In an embodiment, a diluent stream is synchronized with the outputstream of the apparatus to lower the concentration of theperoxycarboxylic acid or acids or mixtures thereof such that the newconcentration is at or below site storage hazard codes. If the diluentis water, the new concentrate will be in a non-equilibrium, perturbedstate. Being only metastable, it will be limited to on-site generated orrefrigerated peroxycarboxylic acid products. Accordingly, in an aspect,the storage concentration is a concentration at which theperoxycarboxylic acid is stable for a short period of time (e.g., 1-3days at 20° C.), such concentration being significantly higher than thetypical use concentration. For example, a 25% solution of peroxyaceticacid is diluted to an 11% solution for storage purposes, and is stableat a concentration of 11% for about 1 to 2 days at 20° C. In anembodiment, the concentrated peroxyacid made using the apparatus of theinvention may be diluted to a storage concentration at the site of use.In an aspect, the storage concentration is a concentration at which theacid is stable for a short period of time (e.g., 1-3 days), suchconcentration being significantly higher than the typical useconcentration. For example, a 25% solution of peroxyacetic acid isdiluted to an 11% solution for storage purposes, and is stable at aconcentration of 11% for about 1 to 2 days at 20° C.

In an embodiment, peroxycarboxylic acid compositions are generated atthe site of use by the apparatus of the invention. The apparatusincludes a percarboxylic acid monitoring device for measuring thepercarboxylic acid concentrations from the catalytic output, dilutedsemi-concentrates as well as highly diluted use solutions. In an aspect,monitoring the concentration of peroxycarboxylic acid provides anassurance that concentrations are being maintained at levels that areconsidered useful and within concentration ranges required by safetystandards at the site of use.

In an embodiment, peroxycarboxylic acid compositions are generated atthe site of use by the apparatus of the invention. The apparatusincludes a monitoring device for measuring one or more properties of thecation exchanger, reagents on the cation exchanger, the cation exchangercolumn assembly as a whole, the catalyst, the reagents on the catalyst,or the catalyst column assembly as a whole, In an aspect, the monitoringdevice can monitor pressure (e.g., increased pressure), temperature(e.g., increased temperature), or both. For example, the monitoringdevice can measure a difference in temperature between two points in oraround (e.g., before and after or before and in) the guard column.

In an embodiment, the stored concentrated peroxycarboxylic acid solutionis useful in the cleaning or sanitizing of containers, processingfacilities, or equipment in the food service or food processingindustries, including, for example, cold or hot aseptic packaging. In anaspect, the stored concentrated peroxycarboxylic acid is diluted to ause concentration, such as, for example, about 100 ppm to about 2000ppm, including about 500 ppm, about 500 ppm to about 1000 ppm, about1000 ppm to about 1500 ppm, 1500 ppm to about 2000 ppm, and likeconcentrations.

In an embodiment, the methods of the present invention involve treatingaseptic packaging with the peroxycarboxylic acid compositions of theinvention at the appropriate use concentration. The methods comprisecontacting the aseptic packaging container with a composition accordingto the present invention. Such contacting can be accomplished using aspray device or soaking tank or vessel to intimately contact the insideof the container with the composition for sufficient period of time toclean or reduce the microbial population in the container. The containeris then emptied of the amount of the present composition used. Afteremptying, the container can then be rinsed with potable water orsterilized water (which can include a rinse additive) and again emptied.After rinsing, the container can be filled with the liquid beverage. Thecontainer is then sealed, capped or closed and then packed for shipmentfor ultimate sale.

Carboxylic Acids, Peroxycarboxylic Acids, and Additional Ingredients

Peroxycarboxylic (or percarboxylic) acids generally have the formulaR(CO₃H)_(n), where, for example, R is an alkyl, arylalkyl, cycloalkyl,aromatic, or heterocyclic group, and n is one, two, or three, and namedby prefixing the parent acid with peroxy. The R group can be saturatedor unsaturated as well as substituted or unsubstituted. Peroxy forms ofcarboxylic acids with more than one carboxylate moiety can have one ormore of the carboxyl moieties present as peroxycarboxyl moieties.

The methods of the invention can employ peroxycarboxylic acidscontaining, for example, 2 to 12 carbon atoms. For example,peroxycarboxylic (or percarboxylic) acids can have the formulaR(CO₃H)_(n), where R is a C₁-C₁₁ alkyl group, a C₁-C₁₁ cycloalkyl, aC₁-C₁₁ arylalkyl group, C₁-C₁₁ aryl group, or a C₁-C₁₁ heterocyclicgroup; and n is one, two, or three. The methods of the invention canemploy a medium chain peroxycarboxylic acid containing, for example, 6to 12 carbon atoms. For example, medium chain peroxycarboxylic (orpercarboxylic) acids can have the formula R(CO₃H)_(n), where R is aC₅-C₁₁ alkyl group, a C₅-C₁₁ cycloalkyl, a C₅-C₁₁ arylalkyl group,C₅-C₁₁ aryl group, or a C₅-C₁₁ heterocyclic group; and n is one, two, orthree. The methods of the invention can employ a short chainperoxycarboxylic acid containing, for example, 1 to 4 carbon atoms. Forexample, short chain peroxycarboxylic (or percarboxylic) acids can havethe formula R(CO₃H)_(n), where R is H, a C₁-C₃ alkyl group, or a C₃cycloalkyl and n is one or two. The mixed peroxycarboxylic acidcomposition employed in the present invention can include one or moreshort chain peroxycarboxylic acids and one or more medium chainperoxycarboxylic acids.

Peroxycarboxylic acids can be made by the direct action of an oxidizingagent on a carboxylic acid, by autoxidation of aldehydes, or from acidchlorides, and hydrides, or carboxylic anhydrides with hydrogen orsodium peroxide. In an embodiment, percarboxylic acid can be made by thedirect, acid catalyzed equilibrium action of hydrogen peroxide on thecarboxylic acid. Scheme 1 illustrates an equilibrium between carboxylicacid and oxidizing agent (Ox) on one side and peroxycarboxylic acid andreduced oxidizing agent (Ox_(red)) on the other:

RCOOH+Ox⇄RCOOOH+Ox _(red)  (1)

Scheme 2 illustrates an embodiment of the equilibrium of scheme 1 inwhich the oxidizing agent is hydrogen peroxide on one side andperoxycarboxylic acid and water on the other:

RCOOH+H₂O₂⇄RCOOOH+H₂O  (2)

In conventional mixed peroxycarboxylic acid compositions it is believedthat the equilibrium constant for the reaction illustrated in scheme 2is about 2.7, which may reflect the equilibrium for acetic acid.

Peroxycarboxylic acids useful in the methods of the present inventioninclude peroxyformic, peroxyacetic, peroxypropionic, peroxybutanoic,peroxypentanoic, peroxyhexanoic, peroxyheptanoic, peroxyoctanoic,peroxynonanoic, peroxydecanoic, peroxyundecanoic, peroxydodecanoic,peroxylactic, peroxymaleic, peroxyascorbic, peroxyhydroxyacetic,peroxyoxalic, peroxymalonic, peroxysuccinic, peroxyglutaric,peroxyadipic, peroxypimelic, peroxysubric acid, or mixtures thereof.Medium chain peroxycarboxylic acids useful in the compositions andmethods of the present invention include peroxypentanoic,peroxyhexanoic, peroxyheptanoic, peroxyoctanoic, peroxynonanoic,peroxydecanoic, peroxyundecanoic, peroxydodecanoic, peroxyascorbic,peroxyadipic, peroxycitric, peroxypimelic, or peroxysuberic acid,mixtures thereof, or the like. Short chain peroxycarboxylic acids usefulin the compositions and methods of the present invention includeperoxyformic, peroxyacetic, peroxypropionic, peroxybutanoic,peroxyoxalic, peroxymalonic, peroxysuccinic acid, mixtures thereof, orthe like. The alkyl backbones of these peroxycarboxylic acids can bestraight chain, branched, or a mixture thereof. Peroxy forms ofcarboxylic acids with more than one carboxylate moiety can have one ormore (e.g., at least one) of the carboxyl moieties present asperoxycarboxyl moieties.

In an embodiment, the methods of the present invention employperoxyacetic acid. Peroxyacetic (or peracetic) acid is aperoxycarboxylic acid having the formula: CH₃COOOOH. Generally,peroxyacetic acid is a liquid having an acrid odor at higherconcentrations and is freely soluble in water, alcohol, ether, andsulfuric acid. A 50% solution of peroxyacetic acid can be obtained bycombining acetic anhydride, hydrogen peroxide and sulfuric acid.

Peroxyoctanoic (or peroctanoic) acid is a peroxycarboxylic acid havingthe formula, for example, of n-peroxyoctanoic acid: CH₃(CH₂)₆COOOH.Peroxyoctanoic acid can be an acid with a straight chain alkyl moiety,an acid with a branched alkyl moiety, or a mixture thereof.Peroxyoctanoic acid is surface active and can assist in wettinghydrophobic surfaces, such as those of an arthropod.

In an embodiment, the method of the invention utilizes a combination ofseveral different peroxycarboxylic acids. Such a combination can includeone or more short chain, e.g., C₂-C₄, peroxycarboxylic acids and one ormore medium chain, e.g., C₇-C₉, peroxycarboxylic acids. For example, theshort chain peroxycarboxylic acid can be peroxyacetic acid and themedium chain peroxycarboxylic acid can be peroxyoctanoic acid. In anembodiment, the methods of the present invention employ a compositionincluding peroxyoctanoic acid, peroxynonanoic acid, or peroxyheptanoicacid, e.g., peroxyoctanoic acid. In an embodiment, the present methodemploys a composition including acetic acid, octanoic acid, peroxyaceticacid, and peroxyoctanoic acid. Such a composition can also include achelating agent.

The present compositions and methods can include a medium chainperoxycarboxylic acid. The medium chain peroxycarboxylic acid caninclude or be a C6 to C12 peroxycarboxylic acid. The C6 to C12peroxycarboxylic acid can include or be peroxyhexanoic acid,peroxyheptanoic acid, peroxyoctanoic acid, peroxynonanoic acid,peroxydecanoic acid, peroxyundecanoic acid, peroxydodecanoic acid, ormixture thereof. The medium chain peroxycarboxylic acid can include orbe a C7 to C12 peroxycarboxylic acid. The C7 to C12 peroxycarboxylicacid can include or be peroxyheptanoic acid, peroxyoctanoic acid,peroxynonanoic acid, peroxydecanoic acid, peroxyundecanoic acid,peroxydodecanoic acid, or mixture thereof. The medium chainperoxycarboxylic acid can include or be a C6 to C10 peroxycarboxylicacid. The C6 to C10 peroxycarboxylic acid can include or beperoxyhexanoic acid, peroxyheptanoic acid, peroxyoctanoic acid,peroxynonanoic acid, peroxydecanoic acid, or mixture thereof. The mediumchain peroxycarboxylic acid can include or be a C8 to C10peroxycarboxylic acid. The C8 to C10 peroxycarboxylic acid can includeor be peroxyoctanoic acid, peroxynonanoic acid, peroxydecanoic acid, ormixture thereof. In certain embodiments, the medium chain peroxyoctanoicacid includes or is peroxyoctanoic acid, peroxydecanoic acid, or mixturethereof. In an embodiment, the medium chain peroxycarboxylic acidincludes or is peroxyoctanoic acid.

The composition of the present invention can include a carboxylic acid.Generally, carboxylic acids have the formula R—COOH wherein the R canrepresent any number of different groups including aliphatic groups,alicyclic groups, aromatic groups, heterocyclic groups, all of which canbe saturated or unsaturated as well as substituted or unsubstituted.Carboxylic acids can have one, two, three, or more carboxyl groups. Thecomposition and methods of the invention can employ carboxylic acidscontaining as many as 18 carbon atoms.

Suitable carboxylic acids include those having one or two carboxylgroups where the R group is a primary alkyl chain having a length of C₂to C₁₂. The primary alkyl chain is that carbon chain of the moleculehaving the greatest length of carbon atoms and directly appendingcarboxyl functional groups. For example, carboxylic acids can have theformula R—COOH in which R can be a C₁-C₁₂ alkyl group, a C₁-C₁₁cycloalkyl group, a C₁-C₁₂ arylalkyl group, C₁-C₁₁ aryl group, or aC₁-C₁₁ heterocyclic group. The methods of the invention can employmedium chain carboxylic acids containing, for example, 6 to 12 carbonatoms. For example, medium chain carboxylic acids can have the formulaR—COOH in which R can be a C₅-C₁₁ alkyl group, a C₅-C₁₁ cycloalkylgroup, a C₅-C₁₁ arylalkyl group, C₅-C₁₁ aryl group, or a C₅-C₁₁heterocyclic group. For example, short chain carboxylic acids can havethe formula R—COOH in which R is H, a C₁-C₃ alkyl group, or a C₃cycloalkyl and n is one or two.

Suitable carboxylic acids include formic, acetic, propionic, butanoic,pentanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic,undecanoic, dodecanoic, lactic, maleic, ascorbic, citric, hydroxyacetic,neopentanoic, neoheptanoic, neodecanoic, oxalic, malonic, succinic,glutaric, adipic, pimelic, subric acid, mixtures thereof, or the like.Suitable medium chain carboxylic acids include pentanoic, hexanoic,heptanoic, octanoic, nonanoic, decanoic, undecanoic, dodecanoic,ascorbic, citric, adipic, pimelic, suberic acid, mixtures thereof, orthe like. Suitable short chain carboxylic acids include formic, acetic,propionic, butanoic, hydroxyacetic, oxalic, malonic, succinic acid,mixtures thereof, or the like. The alkyl backbones of these carboxylicacids can be straight chain, branched, or a mixture thereof. Carboxylicacids which are generally useful are those having one or two carboxylgroups where the R group is a primary alkyl chain having a length of C₄to C₁₁. The primary alkyl chain is that carbon chain of the moleculehaving the greatest length of carbon atoms and directly appendingcarboxyl functional groups.

In an embodiment, the present compositions and methods include a mediumchain carboxylic acid. The medium chain carboxylic acid can include orbe a C6 to C12 carboxylic acid. The C6 to C12 carboxylic acid caninclude or be hexanoic acid, heptanoic acid, octanoic acid, nonanoicacid, decanoic acid, undecanoic acid, dodecanoic acid, or mixturethereof. The medium chain carboxylic acid can include or be a C7 to C12carboxylic acid. The C7 to C12 carboxylic acid can include or beheptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoicacid, dodecanoic acid, or mixture thereof. The medium chainperoxycarboxylic acid can include or be a C6 to C10 carboxylic acid. TheC6 to C10 carboxylic acid can include or be hexanoic acid, heptanoicacid, octanoic acid, nonanoic acid, decanoic acid, or mixture thereof.The medium chain carboxylic acid can include or be a C8 to C10carboxylic acid. The C8 to C10 carboxylic acid can include or beoctanoic acid, nonanoic acid, decanoic acid, or mixture thereof. Incertain embodiments, the medium chain carboxylic acid includes or isoctanoic acid, decanoic acid, or mixture thereof. In an embodiment, themedium chain carboxylic acid includes or is octanoic acid.

In an embodiment, the compositions and methods include mixedperoxycarboxylic acids and the corresponding mixed carboxylic acids.

In an embodiment, the present composition includes an amount of mixedperoxycarboxylic acid effective for killing one or more (e.g., at leastone) of the food-borne pathogenic bacteria associated with a foodproduct, such as Salmonella typhimurium, Salmonella javiana,Campylobacter jejuni, Listeria monocytogenes, and Escherichia coliO157:H7, yeast, mold, and the like. In an embodiment, the presentcomposition includes an amount of mixed peroxycarboxylic acid effectivefor killing one or more (e.g., at least one) of the pathogenic bacteriaassociated with a health care surfaces and environments, such asSalmonella typhimurium, Staphylococcus aureus, Salmonella choleraesurus,Pseudomonas aeruginosa, Escherichia coli, mycobacteria, yeast, mold, andthe like. The compositions and methods of the present invention haveactivity against a wide variety of microorganisms such as Gram positive(for example, Listeria monocytogenes or Staphylococcus aureus) and Gramnegative (for example, Escherichia coli or Pseudomonas aeruginosa)bacteria, yeast, molds, bacterial spores, viruses, etc. The compositionsand methods of the present invention, as described above, have activityagainst a wide variety of human pathogens. The present compositions andmethods can kill a wide variety of microorganisms on a food processingsurface, on the surface of a food product, in water used for washing orprocessing of food product, on a health care surface, or in a healthcare environment.

Carrier

The composition of the invention can also include a carrier. The carrierprovides a medium which dissolves, suspends, or carries the othercomponents of the composition. For example, the carrier can provide amedium for solubilization, suspension, or production of peroxycarboxylicacid and for forming an equilibrium mixture. The carrier can alsofunction to deliver and wet the antimicrobial composition of theinvention on an object. To this end, the carrier can contain anycomponent or components that can facilitate these functions.

Generally, the carrier includes primarily water which can promotesolubility and work as a medium for reaction and equilibrium. Thecarrier can include or be primarily an organic solvent, such as simplealkyl alcohols, e.g., ethanol, isopropanol, n-propanol, and the like.Polyols are also useful carriers, including glycerol, sorbitol, and thelike.

Suitable carriers include glycol ethers. Suitable glycol ethers includediethylene glycol n-butyl ether, diethylene glycol n-propyl ether,diethylene glycol ethyl ether, diethylene glycol methyl ether,diethylene glycol t-butyl ether, dipropylene glycol n-butyl ether,dipropylene glycol methyl ether, dipropylene glycol ethyl ether,dipropylene glycol propyl ether, dipropylene glycol tert-butyl ether,ethylene glycol butyl ether, ethylene glycol propyl ether, ethyleneglycol ethyl ether, ethylene glycol methyl ether, ethylene glycol methylether acetate, propylene glycol n-butyl ether, propylene glycol ethylether, propylene glycol methyl ether, propylene glycol n-propyl ether,tripropylene glycol methyl ether and tripropylene glycol n-butyl ether,ethylene glycol phenyl ether (commercially available as DOWANOL EPH™from Dow Chemical Co.), propylene glycol phenyl ether (commerciallyavailable as DOWANOL PPH™ from Dow Chemical Co.), and the like, ormixtures thereof. Additional suitable commercially available glycolethers (all of which are available from Union Carbide Corp.) includeButoxyethyl PROPASOL™, Butyl CARBITOL™ acetate, Butyl CARBITOL™, ButylCELLOSOLVE™ acetate, Butyl CELLOSOLVE™, Butyl DIPROPASOL™, ButylPROPASOL™, CARBITOL™ PM-600, CARBITOL™ Low Gravity, CELLOSOLVE™ acetate,CELLOSOLVE™, Ester EEP™ FILMER IBT™, Hexyl CARBITOL™, Hexyl CELLOSOLVE™,Methyl CARBITOL™, Methyl CELLOSOLVE™ acetate, Methyl CELLOSOLVE™, MethylDIPROPASOL™ Methyl PROPASOL™ acetate, Methyl PROPASOL™, PropylCARBITOL™, Propyl CELLOSOLVE™, Propyl DIPROPASOL™ and Propyl PROPASOL™

Generally, the carrier makes up a large portion of the composition ofthe invention and may be the balance of the composition apart from theactive antimicrobial components, solubilizer, oxidizing agent,adjuvants, and the like. Here again, the carrier concentration and typewill depend upon the nature of the composition as a whole, theenvironmental storage, and method of application including concentrationof the peroxycarboxylic acid, among other factors. Notably the carriershould be chosen and used at a concentration which does not inhibit theantimicrobial efficacy of the peroxycarboxylic acid in the compositionof the invention.

In certain embodiments, the present composition includes about 0 toabout 98 wt-% carrier, about 0.001 to about 99.99 wt-% carrier, about0.2 to about 60 wt-% carrier, about 1 to about 98 wt-% carrier, about 5to about 99.99 wt-% carrier, about 5 to about 97 wt-% carrier, about 5to about 90 wt-% carrier, about 5 to about 70 wt-% carrier, about 5 toabout 20 wt-% carrier, about 10 to about 90 wt-% carrier, about 10 toabout 80 wt-% carrier, about 10 to about 50 wt-% carrier, about 10 toabout 20 wt-% carrier, about 15 to about 70 wt-% carrier, about 15 toabout 80 wt-% carrier, about 20 to about 70 wt-% carrier, about 20 toabout 50 wt-% carrier, about 20 to about 40 wt-% carrier, about 20 toabout 30 wt-% carrier, about 30 to about 75 wt-% carrier, about 30 toabout 70 wt-% carrier, about 40 to about 99.99 wt-% carrier, about 40 toabout 90 wt-% carrier, or about 60 to about 70 wt-% carrier. Thecomposition can include any of these ranges or amounts not modified byabout.

Oxidizing Agent

The present compositions and methods can include any of a variety ofoxidizing agents. The oxidizing agent can be used for maintaining orgenerating peroxycarboxylic acids.

Examples of inorganic oxidizing agents include the following types ofcompounds or sources of these compounds, or alkali metal salts includingthese types of compounds, or forming an adduct therewith:

hydrogen peroxide;

group 1 (IA) oxidizing agents, for example lithium peroxide, sodiumperoxide, and the like;

group 2 (IIA) oxidizing agents, for example magnesium peroxide, calciumperoxide, strontium peroxide, barium peroxide, and the like;

group 12 (IIB) oxidizing agents, for example zinc peroxide, and thelike;

group 13 (IIIA) oxidizing agents, for example boron compounds, such asperborates, for example sodium perborate hexahydrate of the formulaNa₂[Br₂(O₂)₂(OH)₄].6H₂O (also called sodium perborate tetrahydrate andformerly written as NaBO₃.4H₂O); sodium peroxyborate tetrahydrate of theformula Na₂Br₂(O₂)₂[(OH)₄].4H₂O (also called sodium perboratetrihydrate, and formerly written as NaBO₃.3H₂O); sodium peroxyborate ofthe formula Na₂[B₂(O₂)₂(OH)₄] (also called sodium perborate monohydrateand formerly written as NaBO₃.H₂O); and the like; in an embodiment,perborate;

group 14 (IVA) oxidizing agents, for example persilicates andperoxycarbonates, which are also called percarbonates, such aspersilicates or peroxycarbonates of alkali metals; and the like; in anembodiment, percarbonate; in an embodiment, persilicate;

group 15 (VA) oxidizing agents, for example peroxynitrous acid and itssalts; peroxyphosphoric acids and their salts, for example,perphosphates; and the like; in an embodiment, perphosphate;

group 16 (VIA) oxidizing agents, for example peroxysulfuric acids andtheir salts, such as peroxymonosulfuric and peroxydisulfuric acids, andtheir salts, such as persulfates, for example, sodium persulfate; andthe like; in an embodiment, persulfate;

group VIla oxidizing agents such as sodium periodate, potassiumperchlorate and the like.

Other active inorganic oxygen compounds can include transition metalperoxides; and other such peroxygen compounds, and mixtures thereof.

In an embodiment, the compositions and methods of the present inventionemploy one or more of the inorganic oxidizing agents listed above.Suitable inorganic oxidizing agents include ozone, hydrogen peroxide,hydrogen peroxide adduct, group IIIA oxidizing agent, group VIAoxidizing agent, group VA oxidizing agent, group VIIA oxidizing agent,or mixtures thereof. Suitable examples of such inorganic oxidizingagents include percarbonate, perborate, persulfate, perphosphate,persilicate, or mixtures thereof.

Hydrogen peroxide presents one suitable example of an inorganicoxidizing agent. Hydrogen peroxide can be provided as a mixture ofhydrogen peroxide and water, e.g., as liquid hydrogen peroxide in anaqueous solution. Hydrogen peroxide is commercially available atconcentrations of 35%, 70%, and 90% in water. For safety, the 35% iscommonly used. The present compositions can include, for example, about2 to about 30 wt-% or about 5 to about 20 wt-% hydrogen peroxide.

In an embodiment, the inorganic oxidizing agent includes hydrogenperoxide adduct. For example, the inorganic oxidizing agent can includehydrogen peroxide, hydrogen peroxide adduct, or mixtures thereof. Any ofa variety of hydrogen peroxide adducts are suitable for use in thepresent compositions and methods. For example, suitable hydrogenperoxide adducts include percarbonate salt, urea peroxide, peracetylborate, an adduct of H₂O₂ and polyvinyl pyrrolidone, sodiumpercarbonate, potassium percarbonate, mixtures thereof, or the like.Suitable hydrogen peroxide adducts include percarbonate salt, ureaperoxide, peracetyl borate, an adduct of H₂O₂ and polyvinyl pyrrolidone,or mixtures thereof. Suitable hydrogen peroxide adducts include sodiumpercarbonate, potassium percarbonate, or mixtures thereof, for examplesodium percarbonate.

In an embodiment, the present compositions and methods can includehydrogen peroxide as oxidizing agent. Hydrogen peroxide in combinationwith the percarboxylic acid can provide certain antimicrobial actionagainst microorganisms. Additionally, hydrogen peroxide can provide aneffervescent action which can irrigate any surface to which it isapplied. Hydrogen peroxide can work with a mechanical flushing actiononce applied which further cleans the surface of an object. Anadditional advantage of hydrogen peroxide is the food compatibility ofthis composition upon use and decomposition.

In certain embodiments, the present composition includes about 0.001 toabout 30 wt-% oxidizing agent, about 0.001 to about 10 wt-% oxidizingagent, 0.002 to about 10 wt-% oxidizing agent, about 2 to about 30 wt-%oxidizing agent, about 2 to about 25 wt-% oxidizing agent, about 2 toabout 20 wt-% oxidizing agent, about 4 to about 20 wt-% oxidizing agent,about 5 to about 10 wt-% oxidizing agent, or about 6 to about 10 wt-%oxidizing agent. The composition can include any of these ranges oramounts not modified by about.

Optional Ingredients Acidulant

In an embodiment, the present composition can include an acidulant. Theacidulant can act as a catalyst for conversion of carboxylic acid toperoxycarboxylic acid. The acidulant can be effective to form aconcentrate composition with pH of about 1 or less. The acidulant can beeffective to form a use composition with pH of about 5, about 5 or less,about 4, about 4 or less, about 3, about 3 or less, about 2, about 2 orless, or the like. In an embodiment, the acidulant includes an inorganicacid. Suitable inorganic acids include sulfuric acid, phosphoric acid,nitric acid, hydrochloric acid, methane sulfonic acid, ethane sulfonicacid, propane sulfonic acid, butane sulfonic acid, xylene sulfonic acid,benzene sulfonic acid, mixtures thereof, or the like.

In an embodiment, the acidulant includes a carboxylic acid with pK_(a)less than 4. Suitable carboxylic acids with pK_(a) less than 4 includehydroxyacetic acid, hydroxypropionic acid, other hydroxycarboxylicacids, mixtures thereof, or the like. Such an acidulant is present at aconcentration where it does not act as a solubilizer.

In certain embodiments, the present composition includes about 0.001 toabout 50 wt-% acidulant, about 0.001 to about 30 wt-% acidulant, about 1to about 50 wt-% acidulant, about 1 to about 30 wt-% acidulant, about 2to about 40 wt-% acidulant, about 2 to about 10 wt-% acidulant, about 3to about 40 wt-% acidulant, about 5 to about 40 wt-% acidulant, about 5to about 25 wt-% acidulant, about 10 to about 40 wt-% acidulant, about10 to about 30 wt-% acidulant, about 15 to about 35 wt-% acidulant,about 15 to about 30 wt-% acidulant, or about 40 to about 60 wt-%acidulant. The composition can include any of these ranges or amountsnot modified by about.

Stabilizing Agent

One or more stabilizing agents can be added to the composition of theinvention, for example, to stabilize the peracid and hydrogen peroxideand prevent the premature oxidation of this constituent within thecomposition of the invention.

Suitable stabilizing agents include chelating agents or sequestrants.Suitable sequestrants include organic chelating compounds that sequestermetal ions in solution, particularly transition metal ions. Suchsequestrants include organic amino- or hydroxy-polyphosphonic acidcomplexing agents (either in acid or soluble salt forms), carboxylicacids (e.g., polymeric polycarboxylate), hydroxycarboxylic acids, oraminocarboxylic acids.

The sequestrant can be or include phosphonic acid or phosphonate salt.Suitable phosphonic acids and phosphonate salts include 1-hydroxyethylidene-1,1-diphosphonic acid (CH₃C(PO₃H₂)₂OH) (HEDP);ethylenediamine tetrakis methylenephosphonic acid (EDTMP);diethylenetriamine pentakis methylenephosphonic acid (DTPMP);cyclohexane-1,2-tetramethylene phosphonic acid; amino[tri(methylenephosphonic acid)]; (ethylene diamine[tetra methylene-phosphonic acid)];2-phosphene butane-1,2,4-tricarboxylic acid; or salts thereof, such asthe alkali metal salts, ammonium salts, or alkyloyl amine salts, such asmono, di, or tetra-ethanolamine salts; or mixtures thereof.

Suitable organic phosphonates include HEDP.

Commercially available food additive chelating agents includephosphonates sold under the trade name DEQUEST® including, for example,1-hydroxyethylidene-1,1-diphosphonic acid, available from MonsantoIndustrial Chemicals Co., St. Louis, Mo., as DEQUEST® 2010;amino(tri(methylenephosphonic acid)), (N[CH₂PO₃H₂]₃), available fromMonsanto as DEQUEST® 2000; ethylenediamine[tetra(methylenephosphonicacid)] available from Monsanto as DEQUEST® 2041; and2-phosphonobutane-1,2,4-tricarboxylic acid available from Mobay ChemicalCorporation, Inorganic Chemicals Division, Pittsburgh, Pa., as BayhibitAM.

The sequestrant can be or include aminocarboxylic acid type sequestrant.Suitable aminocarboxylic acid type sequestrants include the acids oralkali metal salts thereof, e.g., amino acetates and salts thereof.Suitable aminocarboxylates include N-hydroxyethylaminodiacetic acid;hydroxyethylenediaminetetraacetic acid, nitrilotriacetic acid (NTA);ethylenediaminetetraacetic acid (EDTA);N-hydroxyethyl-ethylenediaminetriacetic acid (HEDTA);diethylenetriaminepentaacetic acid (DTPA); and alanine-N,N-diaceticacid; and the like; and mixtures thereof.

The sequestrant can be or include a polycarboxylate. Suitablepolycarboxylates include, for example, polyacrylic acid, maleic/olefincopolymer, acrylic/maleic copolymer, polymethacrylic acid, acrylicacid-methacrylic acid copolymers, hydrolyzed polyacrylamide, hydrolyzedpolymethacrylamide, hydrolyzed polyamide-methacrylamide copolymers,hydrolyzed polyacrylonitrile, hydrolyzed polymethacrylonitrile,hydrolyzed acrylonitrile-methacrylonitrile copolymers, polymaleic acid,polyfumaric acid, copolymers of acrylic and itaconic acid, phosphinopolycarboxylate, acid or salt forms thereof, mixtures thereof, and thelike.

In certain embodiments, the present composition includes about 0.5 toabout 50 wt-% sequestrant, about 1 to about 50 wt-% sequestrant, about 1to about 30 wt-% sequestrant, about 1 to about 15 wt-% sequestrant,about 1 to about 5 wt-% sequestrant, about 1 to about 4 wt-%sequestrant, about 2 to about 10 wt-% sequestrant, about 2 to about 5wt-% sequestrant, or about 5 to about 15 wt-% sequestrant. Thecomposition can include any of these ranges or amounts not modified byabout.

In certain embodiments, the present composition includes about 0.001 toabout 50 wt-% stabilizing agent, about 0.001 to about 5 wt-% stabilizingagent, about 0.5 to about 50 wt-% stabilizing agent, about 1 to about 50wt-% stabilizing agent, about 1 to about 30 wt-% stabilizing agent,about 1 to about 10 wt-% stabilizing agent, about 1 to about 5 wt-%stabilizing agent, about 1 to about 3 wt-% stabilizing agent, about 2 toabout 10 wt-% stabilizing agent, about 2 to about 5 wt-% stabilizingagent, or about 5 to about 15 wt-% stabilizing agent. The compositioncan include any of these ranges or amounts not modified by about.

Surfactants Nonionic Surfactants

Suitable nonionic surfactants for use as solvents include alkoxylatedsurfactants. Suitable alkoxylated surfactants include EO/PO copolymers,capped EO/PO copolymers, alcohol alkoxylates, capped alcoholalkoxylates, mixtures thereof, or the like. Suitable alkoxylatedsurfactants for use as solvents include EO/PO block copolymers, such asthe Pluronic and reverse Pluronic surfactants; alcohol alkoxylates, suchas Dehypon LS-54 (R-(EO)₅(PO)₄) and Dehypon LS-36 (R-(EO)₃(PO)₆); andcapped alcohol alkoxylates, such as Plurafac LF221 and Tegoten EC11;mixtures thereof, or the like. When employed as a solvent a surfactant,such as a nonionic surfactant, can be at concentrations higher thanthose conventionally employed as surfactant.

Semi-Polar Nonionic Surfactants

The semi-polar type of nonionic surface active agents are another classof nonionic surfactant useful in compositions of the present invention.Semi-polar nonionic surfactants include the amine oxides, phosphineoxides, sulfoxides and their alkoxylated derivatives.

Amine oxides are tertiary amine oxides corresponding to the generalformula:

wherein the arrow is a conventional representation of a semi-polar bond;and, R¹, R², and R³ may be aliphatic, aromatic, heterocyclic, alicyclic,or combinations thereof. Generally, for amine oxides of detergentinterest, R¹ is an alkyl radical of from about 8 to about 24 carbonatoms; R² and R³ are alkyl or hydroxyalkyl of 1-3 carbon atoms or amixture thereof; R² and R³ can be attached to each other, e.g. throughan oxygen or nitrogen atom, to form a ring structure; R⁴ is an alkyleneor a hydroxyalkylene group containing 2 to 3 carbon atoms; and n rangesfrom 0 to about 20. An amine oxide can be generated from thecorresponding amine and an oxidizing agent, such as hydrogen peroxide.

Useful water soluble amine oxide surfactants are selected from theoctyl, decyl, dodecyl, isododecyl, coconut, or tallow alkyl di-(loweralkyl)amine oxides, specific examples of which are octyldimethylamineoxide, nonyldimethylamine oxide, decyldimethylamine oxide,undecyldimethylamine oxide, dodecyldimethylamine oxide,iso-dodecyldimethyl amine oxide, tridecyldimethylamine oxide,tetradecyldimethylamine oxide, pentadecyldimethylamine oxide,hexadecyldimethylamine oxide, heptadecyldimethylamine oxide,octadecyldimethylaine oxide, dodecyldipropylamine oxide,tetradecyldipropylamine oxide, hexadecyldipropylamine oxide,tetradecyldibutylamine oxide, octadecyldibutylamine oxide,bis(2-hydroxyethyl)dodecylamine oxide,bis(2-hydroxyethyl)-3-dodecoxy-1-hydroxypropylamine oxide,dimethyl-(2-hydroxydodecyl)amine oxide, 3,6,9-trioctadecyldimethylamineoxide and 3-dodecoxy-2-hydroxypropyldi-(2-hydroxyethyl)amine oxide.

Anionic Surfactants

The present composition can include an anionic surfactant assolubilizer. Suitable anionic surfactants include organic sulfonatesurfactant, organic sulfate surfactant, phosphate ester surfactant,carboxylate surfactant, mixtures thereof, or the like. In an embodiment,the anionic surfactant includes alkyl sulfonate, alkylaryl sulfonate,alkylated diphenyl oxide disulfonate, alkylated naphthalene sulfonate,alcohol alkoxylate carboxylate, sarcosinate, taurate, acyl amino acid,alkanoic ester, phosphate ester, sulfuric acid ester, salt or acid formthereof, or mixture thereof. The particular salts will be suitablyselected depending upon the particular formulation and the needstherein.

Suitable anionic surfactants include sulfonic acids (and salts), such asisethionates (e.g. acyl isethionates), alkylaryl sulfonic acids andsalts thereof, alkyl sulfonates, and the like.

Examples of suitable synthetic, water soluble anionic detergentcompounds include the ammonium and substituted ammonium (such as mono-,di- and triethanolamine) and alkali metal (such as sodium, lithium andpotassium) salts of the alkyl mononuclear aromatic sulfonates such asthe alkyl benzene sulfonates containing from about 5 to about 18 carbonatoms in the alkyl group in a straight or branched chain, e.g., thesalts of alkyl benzene sulfonates or of alkyl toluene, xylene, cumeneand phenol sulfonates; alkyl naphthalene sulfonate, diamyl naphthalenesulfonate, and dinonyl naphthalene sulfonate and alkoxylated derivativesor their free acids. Suitable sulfonates include olefin sulfonates, suchas long chain alkene sulfonates, long chain hydroxyalkane sulfonates ormixtures of alkenesulfonates and hydroxyalkane-sulfonates.

In certain embodiments, the present compositions including an anionicsurfactant, such as a normal C8 sulfonate, can be non-foam or low foamcompositions. Such compositions can be advantageous for applicationssuch as clean in place, machine warewashing, destaining, and sanitizing,laundry washing, destaining, and sanitizing, etc.

For applications in which foaming is desirable, a foaming agent can beadded as part of the present composition or separately. In a two-stepoffering, a foaming agent can be combined with a dilution of thenon-foam or low foam composition to form a foaming use solution. In aone-step offering, the foaming agent can be incorporated into theconcentrated composition. One suitable foaming agent is LAS acid. LASacid can form a microemulsion in the present compositions. LAS acid canform a viscoelastic gel or liquid in the present compositions.

Anionic sulfate surfactants suitable for use in the present compositionsinclude alkyl ether sulfates, alkyl sulfates, the linear and branchedprimary and secondary alkyl sulfates, alkyl ethoxysulfates, fatty oleylglycerol sulfates, alkyl phenol ethylene oxide ether sulfates, theC₅-C₁₇ acyl-N—(C₁-C₄ alkyl) and —N—(C₁-C₂ hydroxyalkyl) glucaminesulfates, and sulfates of alkylpolysaccharides such as the sulfates ofalkylpolyglucoside, and the like. Also included are the alkyl sulfates,alkyl poly(ethyleneoxy) ether sulfates and aromatic poly(ethyleneoxy)sulfates such as the sulfates or condensation products of ethylene oxideand nonyl phenol (usually having 1 to 6 oxyethylene groups permolecule).

Anionic carboxylate surfactants suitable for use in the presentcompositions include carboxylic acids (and salts), such as alkanoicacids (and alkanoates), ester carboxylic acids (e.g. alkyl succinates),ether carboxylic acids, and the like. Such carboxylates include alkylethoxy carboxylates, alkyl aryl ethoxy carboxylates, alkyl polyethoxypolycarboxylate surfactants and soaps (e.g. alkyl carboxyls). Secondarycarboxylates useful in the present compositions include those whichcontain a carboxyl unit connected to a secondary carbon. The secondarycarbon can be in a ring structure, e.g. as in p-octyl benzoic acid, oras in alkyl-substituted cyclohexyl carboxylates. The secondarycarboxylate surfactants typically contain no ether linkages, no esterlinkages and no hydroxyl groups. Further, they typically lack nitrogenatoms in the head-group (amphiphilic portion). Suitable secondary soapsurfactants typically contain 11-13 total carbon atoms, although morecarbons atoms (e.g., up to 16) can be present. Suitable carboxylatesalso include acylamino acids (and salts), such as acylgluamates, acylpeptides, sarcosinates (e.g. N-acyl sarcosinates), taurates (e.g. N-acyltaurates and fatty acid amides of methyl tauride), and the like.

Suitable anionic surfactants include alkyl or alkylaryl ethoxycarboxylates of Formula 3:

R—O—(CH₂CH₂O)_(n)(CH₂)_(m)—CO₂X  (3)

in which R is a C₈ to C₂₂ alkyl group or

in which R¹ is a C₄-C₁₆ alkyl group; n is an integer of 1-20; m is aninteger of 1-3; and X is a counter ion, such as hydrogen, sodium,potassium, lithium, ammonium, or an amine salt such as monoethanolamine,diethanolamine or triethanolamine. In an embodiment, in Formula 3, n isan integer of 4 to 10 and m is 1. In an embodiment, in Formula 3, R is aC₈-C₁₆ alkyl group. In an embodiment, in Formula 3, R is a C₁₂-C₁₄ alkylgroup, n is 4, and m is 1.

In an embodiment, in Formula 3, R is

and R¹ is a C₆-C₁₂ alkyl group. In an embodiment, in Formula 3, R¹ is aC₉ alkyl group, n is 10 and m is 1. Such alkyl and alkylaryl ethoxycarboxylates are commercially available. These ethoxy carboxylates aretypically available as the acid forms, which can be readily converted tothe anionic or salt form. Commercially available carboxylates include,Neodox 23-4, a C₁₂₋₁₃ alkyl polyethoxy (4) carboxylic acid (ShellChemical), and Emcol CNP-110, a C₉ alkylaryl polyethoxy (10) carboxylicacid (Witco Chemical). Carboxylates are also available from Clariant,e.g. the product Sandopan® DTC, a C₁₃ alkyl polyethoxy (7) carboxylicacid.

Amphoteric Surfactants

Amphoteric, or ampholytic, surfactants contain both a basic and anacidic hydrophilic group and an organic hydrophobic group. These ionicentities may be any of anionic or cationic groups described herein forother types of surfactants. A basic nitrogen and an acidic carboxylategroup are the typical functional groups employed as the basic and acidichydrophilic groups. In a few surfactants, sulfonate, sulfate,phosphonate or phosphate provide the negative charge.

Amphoteric surfactants can be broadly described as derivatives ofaliphatic secondary and tertiary amines, in which the aliphatic radicalmay be straight chain or branched and wherein one of the aliphaticsubstituents contains from about 8 to 18 carbon atoms and one containsan anionic water solubilizing group, e.g., carboxy, sulfo, sulfato,phosphato, or phosphono. Amphoteric surfactants are subdivided into twomajor classes known to those of skill in the art and described in“Surfactant Encyclopedia” Cosmetics & Toiletries, Vol. 104 (2) 69-71(1989). The first class includes acyl/dialkyl ethylenediaminederivatives (e.g. 2-alkyl hydroxyethyl imidazoline derivatives) andtheir salts. The second class includes N-alkylamino acids and theirsalts. Some amphoteric surfactants can be envisioned as fitting intoboth classes.

Amphoteric surfactants can be synthesized by methods known to those ofskill in the art. For example, 2-alkyl hydroxyethyl imidazoline issynthesized by condensation and ring closure of a long chain carboxylicacid (or a derivative) with dialkyl ethylenediamine. Commercialamphoteric surfactants are derivatized by subsequent hydrolysis andring-opening of the imidazoline ring by alkylation—for example withchloroacetic acid or ethyl acetate. During alkylation, one or twocarboxy-alkyl groups react to form a tertiary amine and an ether linkagewith differing alkylating agents yielding different tertiary amines.

Long chain imidazole derivatives having application in the presentinvention generally have the general formula:

wherein R is an acyclic hydrophobic group containing from about 8 to 18carbon atoms and M is a cation to neutralize the charge of the anion,generally sodium. Commercially prominent imidazoline-derived amphotericsthat can be employed in the present compositions include for example:Cocoamphopropionate, Cocoamphocarboxy-propionate, Cocoamphoglycinate,Cocoamphocarboxy-glycinate, Cocoamphopropyl-sulfonate, andCocoamphocarboxy-propionic acid. Amphocarboxylic acids can be producedfrom fatty imidazolines in which the dicarboxylic acid functionality ofthe amphodicarboxylic acid is diacetic acid and/or dipropionic acid.

The carboxymethylated compounds (glycinates) described herein abovefrequently are called betaines. Betaines are a special class ofamphoteric discussed herein below in the section entitled, ZwitterionSurfactants.

Long chain N-alkylamino acids are readily prepared by reaction RNH₂, inwhich R═C₈-C₁₈ straight or branched chain alkyl, fatty amines withhalogenated carboxylic acids. Alkylation of the primary amino groups ofan amino acid leads to secondary and tertiary amines. Alkyl substituentsmay have additional amino groups that provide more than one reactivenitrogen center. Most commercial N-alkylamine acids are alkylderivatives of beta-alanine or beta-N(2-carboxyethyl) alanine. Examplesof commercial N-alkylamino acid ampholytes having application in thisinvention include alkyl beta-amino dipropionates, RN(C₂H₄COOM)₂ andRNHC₂H₄COOM. In an embodiment, R can be an acyclic hydrophobic groupcontaining from about 8 to about 18 carbon atoms, and M is a cation toneutralize the charge of the anion.

Suitable amphoteric surfactants include those derived from coconutproducts such as coconut oil or coconut fatty acid. Additional suitablecoconut derived surfactants include as part of their structure anethylenediamine moiety, an alkanolamide moiety, an amino acid moiety,e.g., glycine, or a combination thereof; and an aliphatic substituent offrom about 8 to 18 (e.g., 12) carbon atoms. Such a surfactant can alsobe considered an alkyl amphodicarboxylic acid. These amphotericsurfactants can include chemical structures represented as:C₁₂-alkyl-C(O)—NH—CH₂—CH₂—N⁺(CH₂—CH₂—CO₂Na)₂—CH₂—CH₂—OH orC₁₂-alkyl-C(O)—N(H)—CH₂—CH₂—N⁺(CH₂—CO₂Na)₂—CH₂—CH₂—OH. Disodiumcocoampho dipropionate is one suitable amphoteric surfactant and iscommercially available under the tradename Miranol™ FBS from RhodiaInc., Cranbury, N.J. Another suitable coconut derived amphotericsurfactant with the chemical name disodium cocoampho diacetate is soldunder the tradename Mirataine™ JCHA, also from Rhodia Inc., Cranbury,N.J.

A typical listing of amphoteric classes, and species of thesesurfactants, is given in U.S. Pat. No. 3,929,678 issued to Laughlin andHeuring on Dec. 30, 1975. Further examples are given in “Surface ActiveAgents and Detergents” (Vol. I and II by Schwartz, Perry and Berch).

Zwitterionic Surfactants

Zwitterionic surfactants can be thought of as a subset of the amphotericsurfactants and can include an anionic charge. Zwitterionic surfactantscan be broadly described as derivatives of secondary and tertiaryamines, derivatives of heterocyclic secondary and tertiary amines, orderivatives of quaternary ammonium, quaternary phosphonium or tertiarysulfonium compounds. Typically, a zwitterionic surfactant includes apositive charged quaternary ammonium or, in some cases, a sulfonium orphosphonium ion; a negative charged carboxyl group; and an alkyl group.Zwitterionics generally contain cationic and anionic groups which ionizeto a nearly equal degree in the isoelectric region of the molecule andwhich can develop strong “inner-salt” attraction betweenpositive-negative charge centers. Examples of such zwitterionicsynthetic surfactants include derivatives of aliphatic quaternaryammonium, phosphonium, and sulfonium compounds, in which the aliphaticradicals can be straight chain or branched, and wherein one of thealiphatic substituents contains from 8 to 18 carbon atoms and onecontains an anionic water solubilizing group, e.g., carboxy, sulfonate,sulfate, phosphate, or phosphonate. Betaine and sultaine surfactants areexemplary zwitterionic surfactants for use herein.

A general formula for these compounds is:

wherein R¹ contains an alkyl, alkenyl, or hydroxyalkyl radical of from 8to 18 carbon atoms having from 0 to 10 ethylene oxide moieties and from0 to 1 glyceryl moiety; Y is selected from the group consisting ofnitrogen, phosphorus, and sulfur atoms; R² is an alkyl or monohydroxyalkyl group containing 1 to 3 carbon atoms; x is 1 when Y is a sulfuratom and 2 when Y is a nitrogen or phosphorus atom, R³ is an alkylene orhydroxy alkylene or hydroxy alkylene of from 1 to 4 carbon atoms and Zis a radical selected from the group consisting of carboxylate,sulfonate, sulfate, phosphonate, and phosphate groups.

Examples of zwitterionic surfactants having the structures listed aboveinclude:4-[N,N-di(2-hydroxyethyl)-N-octadecylammonio]-butane-1-carboxylate;5-[S-3-hydroxypropyl-S-hexadecylsulfonio]-3-hydroxypentane-1-sulfate;3-[P,P-diethyl-P-3,6,9-trioxatetracosanephosphonio]-2-hydroxypropane-1-phosphate;3-[N,N-dipropyl-N-3-dodecoxy-2-hydroxypropyl-ammonio]-propane-1-phosphonate;3-(N,N-dimethyl-N-hexadecylammonio)-propane-1-sulfonate;3-(N,N-dimethyl-N-hexadecylammonio)-2-hydroxy-propane-1-sulfonate;4-[N,N-di(2(2-hydroxyethyl)-N(2-hydroxydodecyl)ammonio]-butane-1-carboxylate;3-[S-ethyl-S-(3-dodecoxy-2-hydroxypropyl)sulfonio]-propane-1-phosphate;3-[P,P-dimethyl-P-dodecylphosphonio]-propane-1-phosphonate; andS[N,N-di(3-hydroxypropyl)-N-hexadecylammonio]-2-hydroxy-pentane-1-sulfate.The alkyl groups contained in said detergent surfactants can be straightor branched and saturated or unsaturated.

The zwitterionic surfactant suitable for use in the present compositionsincludes a betaine of the general structure:

These surfactant betaines typically do not exhibit strong cationic oranionic characters at pH extremes nor do they show reduced watersolubility in their isoelectric range. Unlike “external” quaternaryammonium salts, betaines are compatible with anionics. Examples ofsuitable betaines include coconut acylamidopropyldimethyl betaine;hexadecyl dimethyl betaine; C₁₂₋₁₄ acylamidopropylbetaine; C₈₋₁₄acylamidohexyldiethyl betaine; 4-C₁₄₋₁₆acylmethylamidodiethylammonio-1-carboxybutane; C₁₆₋₁₈acylamidodimethylbetaine; C₁₂₋₁₆ acylamidopentanediethylbetaine; andC₁₂₋₁₆ acylmethylamidodimethylbetaine.

Sultaines useful in the present invention include those compounds havingthe formula (R(R¹)₂N⁺R²SO³⁻, in which R is a C₆-C₁₈ hydrocarbyl group,each R¹ is typically independently C₁-C₃ alkyl, e.g. methyl, and R² is aC₁-C₆ hydrocarbyl group, e.g. a C₁-C₃ alkylene or hydroxyalkylene group.

A typical listing of zwitterionic classes, and species of thesesurfactants, is given in U.S. Pat. No. 3,929,678 issued to Laughlin andHeuring on Dec. 30, 1975. Further examples are given in “Surface ActiveAgents and Detergents” (Vol. I and II by Schwartz, Perry and Berch).

In an embodiment, the composition of the present invention includes abetaine. For example, the composition can include cocoamidopropylbetaine.

Adjuvants

The antimicrobial composition of the invention can also include anynumber of adjuvants. Specifically, the composition of the invention caninclude antimicrobial solvent, antimicrobial agent, wetting agent,defoaming agent, thickener, a surfactant, foaming agent, solidificationagent, aesthetic enhancing agent (i.e., colorant (e.g., pigment),odorant, or perfume), stabilizing agent (e.g., HEDP) among any number ofconstituents which can be added to the composition. Such adjuvants canbe preformulated with the antimicrobial composition of the invention oradded to the system simultaneously, or even after, the addition of theantimicrobial composition. The composition of the invention can alsocontain any number of other constituents as necessitated by theapplication, which are known and which can facilitate the activity ofthe present invention. The adjuvant(s) can be added to the presentcarboxylic acid composition in the day tank, in a line or conduit afterthe reaction catalyst, or in the apparatus or system using theperoxycarboxylic acid composition.

Antimicrobial Solvent

Any of a variety of solvents can be useful as antimicrobial solvents inthe present compositions. Antimicrobial solvent can be added to usecompositions before use. Suitable antimicrobial solvents includeacetamidophenol; acetanilide; acetophenone; 2-acetyl-1-methylpyrrole;benzyl acetate; benzyl alcohol; benzyl benzoate; benzyloxyethanol;essential oils (e.g., benzaldehyde, pinenes, terpineols, terpinenes,carvone, cinnamealdehyde, borneol and its esters, citrals, ionenes,jasmine oil, limonene, dipentene, linalool and its esters); diesterdicarboxylates (e.g., dibasic esters) such as dimethyl adipate, dimethylsuccinate, dimethyl glutarate (including products available under thetrade designations DBE, DBE-3, DBE-4, DBE-5, DBE-6, DBE-9, DBE-IB, andDBE-ME from DuPont Nylon), dimethyl malonate, diethyl adipate, diethylsuccinate, diethyl glutarate, dibutyl succinate, and dibutyl glutarate;dimethyl sebacate, dimethyl pimelate, dimethyl suberate; dialkylcarbonates such as dimethyl carbonate, diethyl carbonate, dipropylcarbonate, diisopropyl carbonate, and dibutyl carbonate; organo-nitrilessuch as acetonitrile and benzonitrile; and phthalate esters such asdibutyl phthalate, diethylhexyl phthalate, and diethyl phthalate.Mixtures of antimicrobial solvents can be used if desired.

The antimicrobial solvent can be selected based upon the characteristicsof the surface and microbes to which the antimicrobial composition willbe applied and upon the nature of any coating, soil or other materialthat will be contacted by the antimicrobial composition and optionallyremoved from the surface. Polar solvents, and solvents that are capableof hydrogen bonding typically will perform well on a variety of surfacesand microbes and thus, for such applications, can be selected. Incertain applications, the antimicrobial solvent can be selected for ahigh flashpoint (e.g., greater than about 30° C., greater than about 50°C., or greater than about 100° C.), low odor, and low human and animaltoxicity.

In an embodiment, the antimicrobial solvent is compatible as an indirector direct food additive or substance; especially those described in theCode of Federal Regulations (CFR), Title 21—Food and Drugs, parts 170 to186. The compositions of the invention should contain sufficientantimicrobial solvent to provide the desired rate and type of microbialreduction.

The present composition can include an effective amount of antimicrobialsolvent, such as about 0.01 wt-% to about 60 wt-% antimicrobial solvent,about 0.05 wt-% to about 15 wt-% antimicrobial solvent, or about 0.08wt-% to about 5 wt-% antimicrobial solvent.

Additional Antimicrobial Agent

The antimicrobial compositions of the invention can contain anadditional antimicrobial agent. Additional antimicrobial agent can beadded to use compositions before use. Suitable antimicrobial agentsinclude carboxylic esters (e.g., p-hydroxy alkyl benzoates and alkylcinnamates), sulfonic acids (e.g., dodecylbenzene sulfonic acid),iodo-compounds or active halogen compounds (e.g., elemental halogens,halogen oxides (e.g., NaOCl, HOCl, HOBr, ClO₂), iodine, interhalides(e.g., iodine monochloride, iodine dichloride, iodine trichloride,iodine tetrachloride, bromine chloride, iodine monobromide, or iodinedibromide), polyhalides, hypochlorite salts, hypochlorous acid,hypobromite salts, hypobromous acid, chloro- and bromo-hydantoins,chlorine dioxide, and sodium chlorite), organic peroxides includingbenzoyl peroxide, alkyl benzoyl peroxides, ozone, singlet oxygengenerators, and mixtures thereof, phenolic derivatives (e.g., o-phenylphenol, o-benzyl-p-chlorophenol, tert-amyl phenol and C₁-C₆ alkylhydroxy benzoates), quaternary ammonium compounds (e.g.,alkyldimethylbenzyl ammonium chloride, dialkyldimethyl ammonium chlorideand mixtures thereof), and mixtures of such antimicrobial agents, in anamount sufficient to provide the desired degree of microbial protection.

In an embodiment, the present composition can include addedperoxycarboxylic acid and/or hydrogen peroxide.

The present composition can include an effective amount of antimicrobialagent, such as about 0.001 wt-% to about 60 wt-% antimicrobial agent,about 0.01 wt-% to about 15 wt-% antimicrobial agent, or about 0.08 wt-%to about 2.5 wt-% antimicrobial agent.

Hydrotrope

The composition employed in the methods of the invention may alsoinclude a hydrotrope coupler or solubilizer. Such materials can be usedto ensure that the composition remains phase stable and in a singlehighly active aqueous form. Such hydrotrope solubilizers or couplers canbe used at compositions which maintain phase stability but do not resultin unwanted compositional interaction.

Representative classes of hydrotrope solubilizers or coupling agentsinclude an anionic surfactant such as an alkyl sulfate, an alkyl oralkane sulfonate, a linear alkyl benzene or naphthalene sulfonate, asecondary alkane sulfonate, alkyl ether sulfate or sulfonate, an alkylphosphate or phosphonate, dialkyl sulfosuccinic acid ester, sugar esters(e.g., sorbitan esters) and a C₈₋₁₀ alkyl glucoside.

Preferred coupling agents for use in the methods of the inventioninclude n-octane sulfonate and aromatic sulfonates such as an alkyl arylsulfonate (e.g., sodium xylene sulfonate or naphthalene sulfonate). Manyhydrotrope solubilizers independently exhibit some degree ofantimicrobial activity at low pH. Such action adds to the efficacy ofthe invention but is not a primary criterion used in selecting anappropriate solubilizing agent. Since the presence of theperoxycarboxylic acid material in the protonated neutral state providesbeneficial biocidal or antimicrobial activity, the coupling agent shouldbe selected not for its independent antimicrobial activity but for itsability to provide effective single phase composition stability in thepresence of substantially insoluble peroxycarboxylic acid materials andthe more soluble compositions of the invention. Generally, any number ofsurfactants may be used consistent with the purpose of this constituent.

Anionic surfactants useful with the invention include alkylcarboxylates, linear alkylbenzene sulfonates, paraffin sulfonates andsecondary n-alkane sulfonates, sulfosuccinate esters and sulfated linearalcohols.

Zwitterionic or amphoteric surfactants useful with the invention includeθ-N-alkylaminopropionic acids, n-alkyl-θ-iminodipropionic acids,imidazoline carboxylates, n-alky-Iletaines, amine oxides, sulfobetainesand sultaines.

Nonionic surfactants useful in the context of this invention aregenerally polyether (also known as polyalkylene oxide, polyoxyalkyleneor polyalkylene glycol) compounds. More particularly, the polyethercompounds are generally polyoxypropylene or polyoxyethylene glycolcompounds. Typically, the surfactants useful in the context of thisinvention are synthetic organic polyoxypropylene (PO)-polyoxyethylene(EO) block copolymers. These surfactants have a diblock polymerincluding an EO block and a PO block, a center block of polyoxypropyleneunits (PO), and having blocks of polyoxyethylene grated onto thepolyoxypropylene unit or a center block of EO with attached PO blocks.Further, this surfactant can have further blocks of eitherpolyoxyethylene or polyoxypropylene in the molecule. The averagemolecular weight of useful surfactants ranges from about 1000 to about40,000 and the weight percent content of ethylene oxide ranges fromabout 10-80% by weight.

Also useful in the context of this invention are surfactants includingalcohol alkoxylates having EO, PO and BO blocks. Straight chain primaryaliphatic alcohol alkoxylates can be particularly useful as sheetingagents. Such alkoxylates are also available from several sourcesincluding BASF Wyandotte where they are known as “Plurafac” surfactants.A particular group of alcohol alkoxylates found to be useful are thosehaving the general formula R-(EO)_(m)—(PO)_(n) wherein m is an integerof about 2-10 and n is an integer from about 2-20. R can be any suitableradical such as a straight chain alkyl group having from about 6-20carbon atoms.

Other useful nonionic surfactants of the invention include cappedaliphatic alcohol alkoxylates. These end caps include but are notlimited to methyl, ethyl, propyl, butyl, benzyl and chlorine. Usefulalcohol alkoxylated include ethylene diamine ethylene oxides, ethylenediamine propylene oxides, mixtures thereof, and ethylene diamine EO-POcompounds, including those sold under the tradename Tetronic.Preferably, such surfactants have a molecular weight of about 400 to10,000. Capping improves the compatibility between the nonionic and theoxidizers hydrogen peroxide and peroxycarboxylic acid, when formulatedinto a single composition. Other useful nonionic surfactants arealkylpolyglycosides.

Another useful nonionic surfactant of the invention is a fatty acidalkoxylate wherein the surfactant includes a fatty acid moiety with anester group including a block of EO, a block of PO or a mixed block orheteric group. The molecular weights of such surfactants range fromabout 400 to about 10,000, a preferred surfactant has an EO content ofabout 30 to 50 wt-% and wherein the fatty acid moiety contains fromabout 8 to about 18 carbon atoms.

Similarly, alkyl phenol alkoxylates have also been found useful in theinvention. Such surfactants can be made from an alkyl phenol moietyhaving an alkyl group with 4 to about 18 carbon atoms, can contain anethylene oxide block, a propylene oxide block or a mixed ethylene oxide,propylene oxide block or heteric polymer moiety. Preferably suchsurfactants have a molecular weight of about 400 to about 10,000 andhave from about 5 to about 20 units of ethylene oxide, propylene oxideor mixtures thereof.

The concentration of hydrotrope useful in the present inventiongenerally ranges from about 0.1 to about 20 wt-%, preferably from about0.5 to about 10 wt-%, most preferably from about 1 to about 4 wt-%.

Wetting or Defoaming Agents

Also useful in the composition of the invention are wetting anddefoaming agents. Wetting agents function to increase the surfacecontact or penetration activity of the antimicrobial composition of theinvention. Wetting agents which can be used in the composition of theinvention include any of those constituents known within the art toraise the surface activity of the composition of the invention.

Generally, defoamers which can be used in accordance with the inventioninclude silica and silicones; aliphatic acids or esters; alcohols;sulfates or sulfonates; amines or amides; halogenated compounds such asfluorochlorohydrocarbons; vegetable oils, waxes, mineral oils as well astheir sulfated derivatives; fatty acid soaps such as alkali, alkalineearth metal soaps; and phosphates and phosphate esters such as alkyl andalkaline diphosphates, and tributyl phosphates among others; andmixtures thereof.

In an embodiment, the present compositions can include antifoamingagents or defoamers which are of food grade quality given theapplication of the method of the invention. To this end, one of the moreeffective antifoaming agents includes silicones. Silicones such asdimethyl silicone, glycol polysiloxane, methylphenol polysiloxane,trialkyl or tetralkyl silanes, hydrophobic silica defoamers and mixturesthereof can all be used in defoaming applications. Commercial defoamerscommonly available include silicones such as Ardefoam® from ArmourIndustrial Chemical Company which is a silicone bound in an organicemulsion; Foam Kill® or Kresseo® available from Krusable ChemicalCompany which are silicone and non-silicone type defoamers as well assilicone esters; and Anti-Foam A® and DC-200 from Dow CorningCorporation which are both food grade type silicones among others. Thesedefoamers can be present at a concentration range from about 0.01 wt-%to 5 wt-%, from about 0.01 wt-% to 2 wt-%, or from about 0.01 wt-% toabout 1 wt-%.

Thickening or Gelling Agents

The present compositions can include any of a variety of knownthickeners. Suitable thickeners include natural gums such as xanthangum, guar gum, or other gums from plant mucilage; polysaccharide basedthickeners, such as alginates, starches, and cellulosic polymers (e.g.,carboxymethyl cellulose); polyacrylates thickeners; and hydrocolloidthickeners, such as pectin. In an embodiment, the thickener does notleave contaminating residue on the surface of an object. For example,the thickeners or gelling agents can be compatible with food or othersensitive products in contact areas. Generally, the concentration ofthickener employed in the present compositions or methods will bedictated by the desired viscosity within the final composition. However,as a general guideline, the viscosity of thickener within the presentcomposition ranges from about 0.1 wt-% to about 1.5 wt-%, from about 0.1wt-% to about 1.0 wt-%, or from about 0.1 wt-% to about 0.5 wt-%.

Bleaching Agent

The present composition can include a known bleaching agent, such as anactive halogen compound. Suitable bleaching agents include any of thewell known bleaching agents capable of removing stains from suchsubstrates as dishes, flatware, pots and pans, textiles, countertops,appliances, flooring, etc. without significantly damaging the substrate.A nonlimiting list of bleaches includes hypochlorites, chlorides,chlorinated phosphates, chloroisocyanates, chloramines, etc.; andperoxide compounds such as hydrogen peroxide, perborates, percarbonates,etc. Generally, if the application requires a color sensitive activeagent, bleaches such as peroxide compounds are generally preferred.However, if the application does not require color sensitivity, halogenbleaches may be used.

Suitable bleaching agents include those that liberate an active halogenspecies such as chlorine, bromine, hypochlorite ion, hypobromide ion,under conditions normally encountered in typical cleaning processes. Theactive halogen compound can, for example, be a source of a freeelemental halogen or —OX— wherein X is Cl or Br, under conditionsnormally used in detergent-bleaching cleaning processes. In anembodiment, the active halogen compound releases chlorine or brominespecies. In an embodiment, the active halogen compound releaseschlorine.

Chlorine releasing compounds include potassium dichloroisocyanurate,sodium dichloroisocyanurate, chlorinated trisodiumphosphate, calciumhypochlorite, lithium hypochlorite, monochloramine, dichloroamine,[(monotrichloro)-tetra (monopotassium dichloro)]pentaisocyanurate,paratoluene sulfondichloro-amide, trichloromelamine, N-chlorammeline,N-chlorosuccinimide, N,N′-dichloroazodicarbonamide,N-chloro-acetyl-urea, N,N′-dichlorobiuret, chlorinated dicyandiamide,trichlorocyanuric acid, dichloroglycoluril, 1,3-dichloro-5,5-dimethylhydantoin, 1-3-dichloro-5-ethyl-5-methyl hydantoin,1-choro-3-bromo-5-ethyl-5-methyl hydantoin, dichlorohydantoin,trichloromelamine, sulfondichloroamide, trichlorocyanuric acid, salts orhydrates thereof, and mixtures thereof. In an embodiment, an chlorinereleasing compound includes sodium dichloroisocyanurate. In anembodiment, an organic chlorine releasing compound can be sufficientlysoluble in water to have a hydrolysis constant (K) of about 10⁻⁴ orgreater.

Encapsulated chlorine sources may also be used to enhance the stabilityof the chlorine source in the composition (see, for example, U.S. Pat.Nos. 4,618,914 and 4,830,773, the disclosures of which are incorporatedby reference herein).

A bleaching agent may also include an agent containing or acting as asource of active oxygen. The active oxygen compound acts to provide asource of active oxygen, for example, may release active oxygen inaqueous solutions. An active oxygen compound can be inorganic ororganic, or can be a mixture thereof. Some examples of active oxygencompound include peroxygen compounds, or peroxygen compound adducts.Some examples of active oxygen compounds or sources include hydrogenperoxide, perborates, sodium carbonate peroxyhydrate, phosphateperoxyhydrates, potassium permonosulfate, and sodium perborate mono andtetrahydrate, with and without activators such as tetraacetylethylenediamine, and the like.

In an embodiment the bleach is an alkali metal salt of achloroisocyanurate, a hydrate thereof, or a mixture thereof.Dichloroisocyanurate dihydrate, a suitable chlorine releasing compound,is commercially available. This compound can be represented by theformula:

NaCl₂C₃N₃O₃2H₂O.

The composition can also include an effective amount of a known bleachactivator, such as tetraacetylethylene diamine or a metal, such asmanganese.

The composition can include bleaching agent at about 0.5 to 20 wt-%,about 1 to 10 wt-%, or about 2 to 8 wt-% of the composition. Thecomposition can include up to about 10 wt-% bleaching agent, and in someembodiments, about 0.1 to about 6 wt-%.

Use Compositions

The present compositions include concentrate compositions and usecompositions. For example, a concentrate composition can be diluted, forexample with water, to form a use composition. In an embodiment, aconcentrate composition can be diluted to a use solution before toapplication to an object. For reasons of economics, the concentrate canbe marketed and an end user can dilute the concentrate with water or anaqueous diluent to a use solution.

The level of active components in the concentrate composition isdependent on the intended dilution factor and the desired activity ofthe peroxycarboxylic acid compound. Generally, a dilution of about 1fluid ounce to about 20 gallons of water to about 5 fluid ounces toabout 1 gallon of water is used for aqueous antimicrobial compositions.Higher use dilutions can be employed if elevated use temperature(greater than 25° C.) or extended exposure time (greater than 30seconds) can be employed. In the typical use locus, the concentrate isdiluted with a major proportion of water using commonly available tap orservice water mixing the materials at a dilution ratio of about 3 toabout 20 ounces of concentrate per 100 gallons of water.

For example, a use composition can include about 0.01 to about 4 wt-% ofa concentrate composition and about 96 to about 99.99 wt-% diluent;about 0.5 to about 4 wt-% of a concentrate composition and about 96 toabout 99.5 wt-% diluent; about 0.5, about 1, about 1.5, about 2, about2.5, about 3, about 3.5, or about 4 wt-% of a concentrate composition;about 0.01 to about 0.1 wt-% of a concentrate composition; or about0.01, about 0.02, about 0.03, about 0.04, about 0.05, about 0.06, about0.07, about 0.08, about 0.09, or about 0.1 wt-% of a concentratecomposition. Amounts of an ingredient in a use composition can becalculated from the amounts listed above for concentrate compositionsand these dilution factors.

The present methods can employ peroxycarboxylic acid at a concentrationeffective for reducing the population of one or more microorganisms.Such effective concentrations include about 2 to about 500 ppm mediumchain peroxycarboxylic acid, about 2 to about 300 ppm peroxycarboxylicacid, about 5 to about 100 ppm peroxycarboxylic acid, about 5 to about60 ppm peroxycarboxylic acid, about 5 to about 45 ppm peroxycarboxylicacid, about 5 to about 35 ppm peroxycarboxylic acid, about 5 to about 25ppm peroxycarboxylic acid, about 8 to about 50 ppm peroxycarboxylicacid, about 10 to about 500 ppm peroxycarboxylic acid, about 10 to about50 ppm peroxycarboxylic acid, about 40 to about 140 ppm peroxycarboxylicacid, about 100 to about 250 ppm peroxycarboxylic acid, or about 200 toabout 300 ppm peroxycarboxylic acid. In an embodiment, the usecomposition can include about 2 to about 500 ppm peroxycarboxylic acid,about 5 to about 2000 ppm carboxylic acid, about 95 to about 99.99 wt-%carrier and/or diluent (e.g., water); and about 2 to about 23,000 ppmpolyalkylene oxide, capped polyalkylene oxide, alkoxylated surfactant,anionic surfactant, or mixture thereof.

The level of reactive species, such as peroxycarboxylic acids and/orhydrogen peroxide, in a use composition can be affected, typicallydiminished, by organic matter that is found in or added to the usecomposition. For example, when the use composition is a bath or sprayused for washing an object, soil on the object can consume peroxy acidand peroxide. Thus, the present amounts of ingredients in the usecompositions refer to the composition before or early in use, with theunderstanding that the amounts will diminish as organic matter is addedto the use composition.

In an embodiment, the present use composition can be made more acidic bypassing the concentrate through an acidifying column, or by addingadditional acidulant to the use composition.

Other Fluid Compositions

The present and compositions can include a critical, near critical, orsupercritical (densified) fluid and an antimicrobial agent or a gaseouscomposition of an antimicrobial agent. The densified fluid can be a nearcritical, critical, supercritical fluid, or another type of fluid withproperties of a supercritical fluid. Fluids suitable for densificationinclude carbon dioxide, nitrous oxide, ammonia, xenon, krypton, methane,ethane, ethylene, propane, certain fluoroalkanes (e.g.,chlorotrifluoromethane and monofluoromethane), and the like, or mixturesthereof. Suitable fluids include carbon dioxide.

In an embodiment, the present compositions or methods include densifiedcarbon dioxide, peroxycarboxylic acid, and carboxylic acid. Such acomposition can be referred to as a densified fluid peroxycarboxylicacid composition. In another embodiment, the antimicrobial compositionincludes the fluid, an antimicrobial agent, and any of the optional oradded ingredients, but is in the form of a gas.

Densified fluid antimicrobial compositions can be applied by any ofseveral methods known to those of skill in the art. Such methods includeventing at an object a vessel containing densified fluid andantimicrobial agent. The aqueous phase, which includes hydrogenperoxide, is advantageously retained in the device. The vented gasincludes an effective amount of antimicrobial agent making the densifiedfluid peroxycarboxylic acid compositions effective antimicrobial agents.

Because of the high pressure nature of the densified fluid compositionsof the invention, these compositions are typically applied by venting avessel containing the composition through a pressure relief device thatis designed to promote rapid efficient coverage of an object. Devicesincluding such a pressure relief device include sprayers, foggers,foamers, foam pad applicators, brush applicators or any other devicethat can permit the expansion of the fluid materials from high pressureto ambient pressure while applying the material to an object. Thedensified fluid peroxycarboxylic acid composition can also be applied toan object by any of a variety of methods known for applying gaseousagents to an object.

Densified fluid antimicrobial compositions can be made by reacting anoxidizable substrate with an oxidizing agent in a medium comprising adensified fluid to form an antimicrobial composition. This reaction istypically carried out in a vessel suitable for containing a densifiedfluid. Reacting can include adding to the vessel the oxidizablesubstrate and the oxidizing agent, and adding fluid to the vessel toform the densified fluid. In an embodiment, the reaction is between acarboxylic acid and hydrogen peroxide to form the correspondingperoxycarboxylic acid. The hydrogen peroxide is commonly supplied in theform of an aqueous solution of hydrogen peroxide.

Supercritical, subcritical, near supercritical, and other dense fluidsand solvents that can be employed with such fluids are disclosed in U.S.Pat. No. 5,306,350, issued Apr. 26, 1994 to Hoy et al., which isincorporated by reference herein for such disclosure. Supercritical andother dense forms of carbon dioxide, and cosolvents, co-surfactants, andother additives that can be employed with these forms of carbon dioxideare disclosed in U.S. Pat. No. 5,866,005, issued Feb. 2, 1999 toDeSimone et al., which is incorporated by reference herein for suchdisclosure.

Methods Employing the Peroxycarboxylic Acid Compositions

The present invention includes methods employing the presentperoxycarboxylic acid compositions. Typically, these methods employ theantimicrobial or bleaching activity of the peroxycarboxylic acid. Forexample, the invention includes a method for reducing a microbialpopulation, a method for reducing the population of a microorganism onskin, a method for treating a disease of skin, a method for reducing anodor, or a method for bleaching. These methods can operate on an object,surface, in a body or stream of water or a gas, or the like, bycontacting the object, surface, body, or stream with a stabilized esterperoxycarboxylic acid composition of the invention. Contacting caninclude any of numerous methods for applying a composition, such asspraying the composition, immersing the object in the composition, foamor gel treating the object with the composition, or a combinationthereof.

The compositions of the invention can be used for a variety of domesticor industrial applications, e.g., to reduce microbial or viralpopulations on a surface or object or in a body or stream of water. Thecompositions can be applied in a variety of areas including kitchens,bathrooms, factories, hospitals, dental offices and food plants, and canbe applied to a variety of hard or soft surfaces having smooth,irregular or porous topography. Suitable hard surfaces include, forexample, architectural surfaces (e.g., floors, walls, windows, sinks,tables, counters and signs); eating utensils; hard-surface medical orsurgical instruments and devices; and hard-surface packaging. Such hardsurfaces can be made from a variety of materials including, for example,ceramic, metal, glass, wood or hard plastic. Suitable soft surfacesinclude, for example paper; filter media, hospital and surgical linensand garments; soft-surface medical or surgical instruments and devices;and soft-surface packaging. Such soft surfaces can be made from avariety of materials including, for example, paper, fiber, woven ornonwoven fabric, soft plastics and elastomers. The compositions of theinvention can also be applied to soft surfaces such as food and skin(e.g., a hand). The present compositions can be employed as a foaming ornonfoaming environmental sanitizer or disinfectant.

The antimicrobial compositions of the invention can be included inproducts such as sterilants, sanitizers, disinfectants, preservatives,deodorizers, antiseptics, fungicides, germicides, sporicides, virucides,detergents, bleaches, hard surface cleaners, hand soaps, waterless handsanitizers, and pre- or post-surgical scrubs.

The antimicrobial compositions can also be used in veterinary productssuch as mammalian skin treatments or in products for sanitizing ordisinfecting animal enclosures, pens, watering stations, and veterinarytreatment areas such as inspection tables and operation rooms. Thepresent compositions can be employed in an antimicrobial foot bath forlivestock or people.

The present compositions can be employed for reducing the population ofpathogenic microorganisms, such as pathogens of humans, animals, and thelike. The compositions can exhibit activity against pathogens includingfungi, molds, bacteria, spores, and viruses, for example, S. aureus, E.coli, Streptococci, Legionella, Pseudomonas aeruginosa, mycobacteria,tuberculosis, phages, or the like. Such pathogens can cause a varietiesof diseases and disorders, including Mastitis or other mammalian milkingdiseases, tuberculosis, and the like. The compositions of the presentinvention can reduce the population of microorganisms on skin or otherexternal or mucosal surfaces of an animal. In addition, the presentcompositions can kill pathogenic microorganisms that spread throughtransfer by water, air, or a surface substrate. The composition needonly be applied to the skin, other external or mucosal surfaces of ananimal water, air, or surface.

The antimicrobial compositions can also be used on foods and plantspecies to reduce surface microbial populations; used at manufacturingor processing sites handling such foods and plant species; or used totreat process waters around such sites. For example, the compositionscan be used on food transport lines (e.g., as belt sprays); boot andhand-wash dip-pans; food storage facilities; anti-spoilage aircirculation systems; refrigeration and cooler equipment; beveragechillers and warmers, blanchers, cutting boards, third sink areas, andmeat chillers or scalding devices. The compositions of the invention canbe used to treat produce transport waters such as those found in flumes,pipe transports, cutters, slicers, blanchers, retort systems, washers,and the like. Particular foodstuffs that can be treated withcompositions of the invention include eggs, meats, seeds, leaves, fruitsand vegetables. Particular plant surfaces include both harvested andgrowing leaves, roots, seeds, skins or shells, stems, stalks, tubers,corms, fruit, and the like. The compositions may also be used to treatanimal carcasses to reduce both pathogenic and non-pathogenic microbiallevels.

The present composition is useful in the cleaning or sanitizing ofcontainers, processing facilities, or equipment in the food service orfood processing industries. The antimicrobial compositions haveparticular value for use on food packaging materials and equipment, andespecially for cold or hot aseptic packaging. Examples of processfacilities in which the composition of the invention can be employedinclude a milk line dairy, a continuous brewing system, food processinglines such as pumpable food systems and beverage lines, etc. Foodservice wares can be disinfected with the composition of the invention.For example, the compositions can also be used on or in ware washmachines, dishware, bottle washers, bottle chillers, warmers, third sinkwashers, cutting areas (e.g., water knives, slicers, cutters and saws)and egg washers. Particular treatable surfaces include packaging such ascartons, bottles, films and resins; dish ware such as glasses, plates,utensils, pots and pans; ware wash machines; exposed food preparationarea surfaces such as sinks, counters, tables, floors and walls;processing equipment such as tanks, vats, lines, pumps and hoses (e.g.,dairy processing equipment for processing milk, cheese, ice cream andother dairy products); and transportation vehicles. Containers includeglass bottles, PVC or polyolefin film sacks, cans, polyester, PEN or PETbottles of various volumes (100 ml to 2 liter, etc.), one gallon milkcontainers, paper board juice or milk containers, etc.

The antimicrobial compositions can also be used on or in otherindustrial equipment and in other industrial process streams such asheaters, cooling towers, boilers, retort waters, rinse waters, asepticpackaging wash waters, and the like. The compositions can be used totreat microbes and odors in recreational waters such as in pools, spas,recreational flumes and water slides, fountains, and the like.

A filter containing the composition can reduce the population ofmicroorganisms in air and liquids. Such a filter can remove water andair-born pathogens such as Legionella.

The present compositions can be employed for reducing the population ofmicrobes, fruit flies, or other insect larva on a drain or othersurface.

The composition may also be employed by dipping food processingequipment into the use solution, soaking the equipment for a timesufficient to sanitize the equipment, and wiping or draining excesssolution off the equipment, The composition may be further employed byspraying or wiping food processing surfaces with the use solution,keeping the surfaces wet for a time sufficient to sanitize the surfaces,and removing excess solution by wiping, draining vertically, vacuuming,etc.

The composition of the invention may also be used in a method ofsanitizing hard surfaces such as institutional type equipment, utensils,dishes, health care equipment or tools, and other hard surfaces. Thecomposition may also be employed in sanitizing clothing items or fabricwhich have become contaminated. The use solution is contacted with anyof the above contaminated surfaces or items at use temperatures in therange of about 4° C. to 60° C., for a period of time effective tosanitize, disinfect, or sterilize the surface or item. For example, theconcentrate composition can be injected into the wash or rinse water ofa laundry machine and contacted with contaminated fabric for a timesufficient to sanitize the fabric. Excess solution can then be removedby rinsing or centrifuging the fabric.

The antimicrobial compositions can be applied to microbes or to soiledor cleaned surfaces using a variety of methods. These methods canoperate on an object, surface, in a body or stream of water or a gas, orthe like, by contacting the object, surface, body, or stream with acomposition of the invention. Contacting can include any of numerousmethods for applying a composition, such as spraying the composition,immersing the object in the composition, foam or gel treating the objectwith the composition, or a combination thereof.

A concentrate or use concentration of a composition of the presentinvention can be applied to or brought into contact with an object byany conventional method or apparatus for applying an antimicrobial orcleaning composition to an object. For example, the object can be wipedwith, sprayed with, foamed on, and/or immersed in the composition, or ause solution made from the composition. The composition can be sprayed,foamed, or wiped onto a surface; the composition can be caused to flowover the surface, or the surface can be dipped into the composition.Contacting can be manual or by machine. Food processing surfaces, foodproducts, food processing or transport waters, and the like can betreated with liquid, foam, gel, aerosol, gas, wax, solid, or powderedstabilized compositions according to the invention, or solutionscontaining these compositions.

The composition can be employed for bleaching pulp. Such a methodincludes contacting the pulp with a peroxycarboxylic acid compositionaccording to the present invention. Such a peroxycarboxylic acidcomposition can include added bleaching agent.

The compositions can be employed for waste treatment. Such a methodincludes contacting the waste with a peroxycarboxylic acid compositionaccording to the present invention. Such a peroxycarboxylic acidcomposition can include added bleaching agent.

Clean in Place

Other hard surface cleaning applications for the antimicrobialcompositions of the invention include clean-in-place systems (CIP),clean-out-of-place systems (COP), washer-decontaminators, sterilizers,textile laundry machines, ultra and nano-filtration systems and indoorair filters. COP systems can include readily accessible systemsincluding wash tanks, soaking vessels, mop buckets, holding tanks, scrubsinks, vehicle parts washers, non-continuous batch washers and systems,and the like.

Generally, the actual cleaning of the in-place system or other surface(i.e., removal of unwanted offal therein) is accomplished with adifferent material such as a formulated detergent which is introducedwith heated water. After this cleaning step, the instant compositionwould be applied or introduced into the system at a use solutionconcentration in unheated, ambient temperature water. CIP typicallyemploy flow rates on the order of about 40 to about 600 liters perminute, temperatures from ambient up to about 70° C., and contact timesof at least about 10 seconds, for example, about 30 to about 120seconds. The present composition can remain in solution in cold (e.g.,40° F./4° C.) water and heated (e.g., 140° F./60° C.) water. Although itis not normally necessary to heat the aqueous use solution of thepresent composition, under some circumstances heating may be desirableto further enhance its antimicrobial activity. These materials areuseful at any conceivable temperatures.

A method of sanitizing substantially fixed in-place process facilitiesincludes the following steps. The use solution of the invention isintroduced into the process facilities at a temperature in the range ofabout 4° C. to 60° C. After introduction of the use solution, thesolution is held in a container or circulated throughout the system fora time sufficient to sanitize the process facilities (i.e., to killundesirable microorganisms). After the surfaces have been sanitized bymeans of the present composition, the use solution is drained. Uponcompletion of the sanitizing step, the system optionally may be rinsedwith other materials such as potable water. The composition can becirculated through the process facilities for 10 minutes or less.

The present method can include delivering the present composition viaair delivery to the clean-in-place or other surfaces such as thoseinside pipes and tanks. This method of air delivery can reduce thevolume of solution required.

Contacting a Food Product with the Peroxycarboxylic Acid Composition

The present method and system provide for contacting a food product witha peroxycarboxylic acid composition employing any method or apparatussuitable for applying such a composition. For example, the method andsystem of the invention can contact the food product with a spray of thecomposition, by immersion in the composition, by foam or gel treatingwith the composition, or the like. Contact with a spray, a foam, a gel,or by immersion can be accomplished by a variety of methods known tothose of skill in the art for applying antimicrobial agents to food.Contacting the food product can occur in any location in which the foodproduct might be found, such as field, processing site or plant,vehicle, warehouse, store, restaurant, or home. These same methods canalso be adapted to apply the stabilized compositions of the invention toother objects.

The present methods require a certain minimal contact time of thecomposition with food product for occurrence of significantantimicrobial effect. The contact time can vary with concentration ofthe use composition, method of applying the use composition, temperatureof the use composition, amount of soil on the food product, number ofmicroorganisms on the food product, type of antimicrobial agent, or thelike. The exposure time can be at least about 5 to about 15 seconds.

In an embodiment, the method for washing food product employs a pressurespray including the composition. During application of the spraysolution on the food product, the surface of the food product can bemoved with mechanical action, e.g., agitated, rubbed, brushed, etc.Agitation can be by physical scrubbing of the food product, through theaction of the spray solution under pressure, through sonication, or byother methods. Agitation increases the efficacy of the spray solution inkilling micro-organisms, perhaps due to better exposure of the solutioninto the crevasses or small colonies containing the micro-organisms. Thespray solution, before application, can also be heated to a temperatureof about 15 to 20° C., for example, about 20 to 60° C. to increaseefficacy. The spray stabilized composition can be left on the foodproduct for a sufficient amount of time to suitably reduce thepopulation of microorganisms, and then rinsed, drained, or evaporatedoff the food product.

Application of the material by spray can be accomplished using a manualspray wand application, an automatic spray of food product moving alonga production line using multiple spray heads to ensure complete contact,or other spray apparatus. One automatic spray application involves theuse of a spray booth. The spray booth substantially confines the sprayedcomposition to within the booth. The production line moves the foodproduct through the entryway into the spray booth in which the foodproduct is sprayed on all its exterior surfaces with sprays within thebooth. After a complete coverage of the material and drainage of thematerial from the food product within the booth, the food product canthen exit the booth. The spray booth can include steam jets that can beused to apply the stabilized compositions of the invention. These steamjets can be used in combination with cooling water to ensure that thetreatment reaching the food product surface is less than 65° C., e.g.,less than 60° C. The temperature of the spray on the food product isimportant to ensure that the food product is not substantially altered(cooked) by the temperature of the spray. The spray pattern can bevirtually any useful spray pattern.

Immersing a food product in a liquid stabilized composition can beaccomplished by any of a variety of methods known to those of skill inthe art. For example, the food product can be placed into a tank or bathcontaining the stabilized composition. Alternatively, the food productcan be transported or processed in a flume of the stabilizedcomposition. The washing solution can be agitated to increase theefficacy of the solution and the speed at which the solution reducesmicro-organisms accompanying the food product. Agitation can be obtainedby conventional methods, including ultrasonics, aeration by bubbling airthrough the solution, by mechanical methods, such as strainers, paddles,brushes, pump driven liquid jets, or by combinations of these methods.The washing solution can be heated to increase the efficacy of thesolution in killing micro-organisms. After the food product has beenimmersed for a time sufficient for the desired antimicrobial effect, thefood product can be removed from the bath or flume and the stabilizedcomposition can be rinsed, drained, or evaporated off the food product.

In another alternative embodiment of the present invention, the foodproduct can be treated with a foaming version of the composition. Thefoam can be prepared by mixing foaming surfactants with the washingsolution at time of use. The foaming surfactants can be nonionic,anionic or cationic in nature. Examples of useful surfactant typesinclude, but are not limited to the following: alcohol ethoxylates,alcohol ethoxylate carboxylate, amine oxides, alkyl sulfates, alkylether sulfate, sulfonates, quaternary ammonium compounds, alkylsarcosines, betaines and alkyl amides. The foaming surfactant istypically mixed at time of use with the washing solution. Use solutionlevels of the foaming agents is from about 50 ppm to about 2.0 wt-%. Attime of use, compressed air can be injected into the mixture, thenapplied to the food product surface through a foam application devicesuch as a tank foamer or an aspirated wall mounted foamer.

In another alternative embodiment of the present invention, the foodproduct can be treated with a thickened or gelled version of thecomposition. In the thickened or gelled state the washing solutionremains in contact with the food product surface for longer periods oftime, thus increasing the antimicrobial efficacy. The thickened orgelled solution will also adhere to vertical surfaces. The compositionor the washing solution can be thickened or gelled using existingtechnologies such as: xanthan gum, polymeric thickeners, cellulosethickeners, or the like. Rod micelle forming systems such as amineoxides and anionic counter ions could also be used. The thickeners orgel forming agents can be used either in the concentrated product ormixing with the washing solution, at time of use. Typical use levels ofthickeners or gel agents range from about 100 ppm to about 10 wt-%.

Aseptic Packaging

In the method of the present invention, aseptic packaging includescontacting the container with a composition according to the presentinvention. Such contacting can be accomplished using a spray device orsoaking tank or vessel to intimately contact the inside of the containerwith the composition for sufficient period of time to clean or reducethe microbial population in the container. The container is then emptiedof the amount of the present composition used. After emptying, thecontainer can then be rinsed with potable water or sterilized water(which can include a rinse additive) and again emptied. After rinsing,the container can be filled with the liquid beverage. The container isthen sealed, capped or closed and then packed for shipment for ultimatesale.

FIG. 18 shows a schematic for an embodiment of a bottlespraying/bottling operation using a composition according to the presentinvention. The operation can be a cold aseptic operation. FIG. 18 showsa plant 100 that can contact beverage bottles with a medium chainperoxycarboxylic acid composition for a sanitizing regime. In FIG. 18,bottles 110 are passed through a sterilizing tunnel 102. The sanitizedbottles 110 a then pass through a rinsing tunnel 103 and emerge assanitized rinsed bottles 110 b.

In the process, bulk medium chain peroxycarboxylic acid composition isadded to a holding tank 101. Commonly, the materials are maintained at atemperature of about 22° C. in tank 101. To obtain the effective useconcentration of the medium chain peroxycarboxylic acid composition,make-up water 105 is combined with the concentrated medium chainperoxycarboxylic acid composition into the tank 101. The medium chainperoxycarboxylic acid use composition is passed through a heater 108 toreach a temperature of about 45-50° C. The heated medium chainperoxycarboxylic acid use composition is sprayed within sterilizingtunnel 102 into and onto all surfaces of the bottle 110. An intimatecontact between the medium chain peroxycarboxylic acid composition andthe bottle 110 is essential for reducing microbial populations to asanitizing level.

After contact with the medium chain peroxycarboxylic acid usecomposition and after dumping any excess composition from the bottles,the sanitized bottles 110 are then passed to a fresh water rinse tunnel103. Fresh water 108 is provided from a fresh water make-up into a sprayrinsing tunnel 103. The fresh water can include a rinse additive. Excessspray drains from rinsing tunnel 103 to drain 106. Within the tunnel103, sanitized bottles 110 a are thoroughly rinsed with fresh water. Thecomplete removal of the medium chain peroxycarboxylic acid compositionfrom the bottles 110 a is important for maintaining high quality of thebeverage product. The rinsed and sanitized bottles 110 b are thenremoved from the rinsing tunnel.

The day tank 101, the sterilizing tunnel 102 and the rinsing tunnel 103are all respectively vended to wet scrubber or vent 111 a, 111 b or 111c to remove vapor or fumes from the system components. The sanitizermaterial that has been sprayed and drained from the bottles 110 aaccumulate in the bottom of the spray tunnel 102 and is then recycledthrough recycle line and heater 107 into the day tank 101.

The contact between the bottles and the medium chain peroxycarboxylicacid antimicrobial composition can be at a temperature of greater thanabout 0° C., greater than 25° C., or greater than about 40° C.Temperatures between about 40° C. and 90° C. can be used. In certainembodiments, contact at 40° C. to 60° C. for at least 5 sec, for exampleat least about 10 sec, contact time is employed.

In the cold aseptic filling of 16 ounce polyethylene terephthalate (PETbottle), or other polymeric, beverage containers, a process has beenadopted using a medium chain peroxycarboxylic acid composition. Themedium chain peroxycarboxylic acid composition can be diluted to a useconcentration of about 0.1 to about 10 wt % and maintained at aneffective elevated temperature of about 25° C. to about 70° C., e.g.,about 40° C. to about 60° C. The spray or flood of the bottle with thematerial ensures contact between the bottle and the sanitizer materialfor at least 5, e.g., about 10, seconds. After flooding is complete, thebottle can be drained of all contents for a minimum of 2 seconds andoptionally followed by a 5 second water rinse with sterilized waterusing about 200 milliliters of water at 38° C. (100° F.). If optionallyfilled with the rinse water, the bottle is then drained of thesterilized water rinse for at least 2 seconds and is immediately filledwith liquid beverage. The rinse water can include a rinse additive.After the rinse is complete, the bottles usually maintain less than 10,e.g., 3, milliliters of rinse water after draining.

Textile Cleaning

The present invention includes methods and compositions for removingsoil from textiles. The composition of the invention can be used withtypical commercial textile cleaning or laundering processes andmachines. The present method can include contacting a laundry item in alaundry machine with a penetrant composition in the form of an aqueouspresoak, preflush, prewash, or other step prior to the cleaning step. Asuitable laundry process employs a washer/extractor. Laundry cleaningprocesses can include processes such as flushing, sudsing, draining,bleaching, rinsing, extracting, repetitions thereof, or combinationsthereof. The bleaching composition can include a composition accordingto the present invention.

Flushing can include contacting the laundry item with a flushingcomposition. In an embodiment, flushing is the initial wetting step inthe machine that carries out the washing procedure. A method of cleaninglaundry can include flushing one, two, or more times. Conventionalflushing compositions are water (e.g., soft or tap water). Inconventional systems, flushing can separate loose soil from and wet alaundry item, but little more. Flushing can also be referred to aspresoaking, preflushing, or prewashing.

Sudsing can include cleaning the laundry item with a sudsing cleaningcomposition. The sudsing cleaning composition typically includessurfactants and other cleaners, and can include a bleach. Sudsing canfollow flushing.

Draining includes removing a cleaning, flushing, or other compositionfrom the laundry item, for example, by gravity and/or centrifugal force.Draining can follow sudsing. Draining can occur between repeats offlushing. In an embodiment, the textile is cleaned with a textilecleaning composition including a built detergent and chlorine bleach ina suds/bleach combination or in two separate wash steps, i.e. suds stepswith built detergent followed by bleach step with chlorine.

Bleaching can include cleaning the laundry item with a bleachcomposition. Bleaching can follow draining and/or sudsing. The bleachingcomposition can include a composition according to the presentinvention.

Rinsing can include contacting the laundry item with a rinse compositionsuitable for removing remaining cleaning (sudsing and/or bleach)composition. The rinse composition can, for example, be water (e.g.,soft or tap water), a sour rinse, or a rinse including softener. Amethod of cleaning laundry can include one, two, three, or more rinses.Rinsing can follow bleaching and/or sudsing.

Extracting can include removing a rinse composition from the laundryitem, typically with centrifugal force. Extracting can follow one ormore rinsings.

The present method and composition can be employed on any of a varietyof textiles. Suitable textiles include cotton, cotton/polyester blend,polyester, and the like.

The present invention may be better understood with reference to thefollowing examples. These examples are intended to be representative ofspecific embodiments of the invention, and are not intended as limitingthe scope of the invention.

EXAMPLES Example 1 Making Peroxyacetic Acid with an Apparatus Includinga Pretreatment Column and a Reaction Catalyst

The present apparatus and method were employed to make the compositionson Tables 1 through 4 below. All equilibrium values were calculatedvalues from the reported K_(eq) of 2.70 for peroxyacetic acid. In thecase of mixed peracids etc., the K_(eq) was assumed to be 2.70.

The stability of certain of the test compositions was monitored with andwithout stabilizer (HEDP) added.

TABLE 1 Wt-% at Initial wt-% Equilibrium Carboxylic Hydrogen PeroxyHydrogen Test Acid Peroxide Water Total Acid Peroxide I 56.5 30.5 13.0100.0 35.3 14.6 II 43.6 20.5 35.9 100.0 17.3 12.7 III 20.0 28.0 52.0100.0 9.7 23.6 IV 78.0 7.7 14.3 100.0 13.1 1.9 V 5.0 5.0 90.0 100.0 0.54.8

TABLE 2 Short Wt-% at Chain Initial wt-% Equilibrium Carboxylic HydrogenPeroxy Hydrogen Test Acid Peroxide Water Total Acid Peroxide VI 56.530.5 13.0 100.0 35.3 14.6 VII 43.6 20.5 35.9 100.0 17.3 12.7 VIII 20.028.0 52.0 100.0  9.7 23.6 IX 78.0  7.7 14.3 100.0 13.1  1.9 X  5.0  5.090.0 100.0  0.5  4.8

TABLE 3 Medium Initial Wt-% at Chain wt-% Equilibrium CarboxylicHydrogen Hydro- Peroxy Hydrogen Test Acid Peroxide trope Water TotalAcid Peroxide XI 20.0 30.0 25 25.0 100.0 18.5 31.7 XII 10.0 20.0 15 55.0100.0  6.8 20.4 XIII  5.0 20.0 10 65.0 100.0  2.1 21.3 XIV  3.0 22.5 1064.5 100.0  1.2 21.6

TABLE 4 Initial wt-% Wt-% at Equilibrium Short Chain Medium Chain MediumCarboxylic Carboxylic Hydrogen Short Chain Chain Peroxy Hydrogen TestAcid Acid Peroxide Hydrotrope Water Total Peroxy Acid Acid Peroxide XV48.0 20.0 10.0 12 10.0 100 13.6 5.7  2.8 XVI 56.0  8.0 12.0 12 12.0 10018.8 2.7  4.0 XVII 60.0  2.0 13.0 12 13.0 100 22.1 0.7  4.6 XVIII 43.6 1.0 20.5  0 34.9 100 17.4 0.4 12.6

TABLE 5 Initial wt-% Measured Output Hydrogen Peroxy of PercarboxylicPredicted % of Test Carboxylic Acid Peroxide Water Total Acid Acid(wt-%) Peracid Pred. XIX Acetic acid 11 30 59 100 5.3 5.6 95 XX Aceticacid 20 28 52 100 9.2 9.7 95 XXI Acetic acid 44 18 38 100 14.3 15.3 93XXII Acetic acid 78  7 15 100 13.0 12.6 103 XXIV Acetic acid 41 17 42100 12.0 13.4 90 XXV Acetic acid 50 20 30 100 20.0 19.9 101 XXVI Aceticacid 60 20 20 100 25.0 25.2 99 XXVII Acetic acid  5  5 90 100 0.4 0.5 78XXVIII Glycolic acid 55  8 38 100 1.2 8.3 14 XXIX Succinic acid  7  3 90100 0.2 0.4 51 XXX Octanoic acid 50 18 32 100 0.54 16.0 3 XXXI Aceticacid 46 19 35 100 17.0 17.2 99 XXXII Acetic acid 50 20 30 100 20.2 19.9102

TABLE 6 Stability of Peracetic Acid Products from Dowex M31 Catalyst at70° F. Measured Concentration of Peracetic Acid (wt-%) Time (days) XXV(no HEDP) XXV (HEDP added) 0.0 18.3 18.9 7.0 19.0 19.1 13.0 19.1 19.0

TABLE 7 Stability of Peracetic Acid Products From Dowex M31 Catalyst at140° F. Measured Concentration of Peracetic Acid (wt-%) Time (days) XXVI(no HEDP) XXV (HEDP added) 0.0 18.3 18.9 7.0 15.8 15.4 13.0 15.8 14.3

TABLE 8 Stability of Peracetic Acid Products From Dowex M31 Catalyst at70° F. Measured Concentration of Peracetic Acid (wt-%) Time (days) XXVI(no HEDP) XXVI (HEDP added) 0.0 25.7 25.7 3.0 23.6 22.8

It should be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the content clearly dictates otherwise. Thus, for example,reference to a composition containing “a compound” includes a mixture oftwo or more compounds. It should also be noted that the term “or” isgenerally employed in its sense including “and/or” unless the contentclearly dictates otherwise.

All publications and patent applications in this specification areindicative of the level of ordinary skill in the art to which thisinvention pertains.

The invention has been described with reference to various specific andpreferred embodiments and techniques. However, it should be understoodthat many variations and modifications may be made while remainingwithin the spirit and scope of the invention.

We claim:
 1. A method for reducing population of a microbe on an object,comprising: delivering carboxylic acid and oxidizing agent to a site atwhich a peroxycarboxylic acid composition will be made and used;providing a liquid composition of the carboxylic acid and oxidizingagent; pretreating the liquid composition with a pretreatment column toremove metal before mixing the carboxylic acid and the oxidizing agentto form a mixed composition; reacting the pretreated composition in thepresence of a reaction catalyst that can be physically removed fromreaction mixture to produce the peroxycarboxylic acid composition;recovering the peroxycarboxylic acid composition; and applying theperoxycarboxylic acid composition to an object to reduce the populationof microbe on the object.
 2. The method of claim 1 further comprisingdelivering a plurality of carboxylic acids to the site.
 3. The method ofclaim 1 further comprising requesting delivery of the carboxylic acidand the oxidizing agent from the site.
 4. The method of claim 1 furthercomprising applying the peroxycarboxylic acid composition to asepticpackaging containers.